What can I do
to help my child with fact and computational fluency at home?
The state of Ohio requires
certain levels of fluency at each grade level.
Fluency is
defined as efficiency, accuracy, and flexibility.
Although repetitive
practice can be helpful once students know facts and computational strategies,
repetitive practice will not help students to learn facts and computation in
the first place, at least not if our goal is for students to remember them
long-term and apply them appropriately in a variety of situations.
So, it is
extremely important to help students learn facts and computation in meaningful
ways before repetitive practice is required. The information below will provide you with ways to work
with children at each grade level.
**If you would like a paper copy
of anything on this page, you can simply copy and paste the text that you want
into a Word document; then print it.
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Kindergarten
No
formal fact or computational knowledge is required at this level. However, some very beneficial
activities with your child are:
- Have your child count objects, and ask
your child to count the same objects after they are moved around to see
that the total has not changed.
Then have your child write the number down and say it again so that
connections are made among the concrete, word, and symbolic
representations of the number.
- Give your child a number from 0-19,
and ask him/her to tell you the next number. (You say 7; child says 8.) Then have your child write both numbers and say them
again. The more challenging
variation of this is to ask your child to give you the number before (1
less than) the number you have said.
- Using a number cube with up to 6 dots
on a side, have your child tell you how many dots are there on a
side. Then have your child
write the number down and say it again. The more that your child can quickly recognize the
number of dots without counting (after doing this many times), the more
that he/she will be able to use that mental image of the number in
thinking about and solving problems.
Very beneficial! If
your child masters the number cube, using dominoes is a good way to move
this activity up a level.
- Give your child two numbers between 0
and 10, and have him/her tell you which is larger. At first, it may be helpful for
your child to count objects for each number to be sure that he/she
understands why the larger one is larger.
- Put out a number of objects (between 0
and 10), and ask your child to add 1 or 2 to the set and tell you how many
are there now. Then have your
child write the original total and the new total.
Grade 1
In
first grade, we start to develop strategies for learning addition and
subtraction facts with students.
In our fluency plan, we work on several specific strategies that are
also in the Ohio standards. (See
these strategies below.) The state
does not require any memorized facts by the end of grade 1.
- Add zero: Have your child put out between 1 and
10 objects and add nothing to them.
Have him/her say the original total and the new total. Then, have your child write a
number sentence that shows what the model shows (for example: 7 + 0 = 7).
- Add to zero: Have your child start with nothing on
the table; then have him/her add between 1 and 10 objects. Have him/her say the original
total and the new total.
Then, have your child write a number sentence that shows what the
model shows (for example: 0 + 5 = 5).
- Turn-around facts (actually the commutative property):
Once your child starts learning addition facts, it is helpful to discuss
with him/her what happens when two numbers are added in either order (for
example, 6 + 0 or 0 + 6).
Have your child write examples such as 0 + 3 = 3 + 0. This should not be done, however,
without modeling these facts with concrete items first and talking about
them.
- One more: Have your child put out between 1 and
10 objects and add one to them.
Have him/her say the original total and the new total. Then, have your child write a
number sentence that shows what the model shows (for example: 4 + 1 = 5).
- Two more: Have your child put out between 1 and
10 objects and add two to them.
Have him/her say the original total and the new total. Then, have your child write a
number sentence that shows what the model shows (for example: 6 + 2 = 8).
- Doubles (addition): Doubles facts are often easy to remember for students,
and they help to build a foundation for many other facts. Dominoes and many other real-life
items that come in pairs (like juice boxes, eggs, pudding cups, etc.) are
great for helping students to picture and learn these facts. Have your students look for or
create models of doubles and then write number sentences for them. (for example: 6 + 6 = 12)
- Subtract zero: Have your child put out between 1 and 10 objects and take
away nothing from them. Have
him/her say the original total and the new total. Then, have your child write a
number sentence that shows what the model shows (for example: 9 - 0 = 9).
- Subtract all: Have your child put out between 1 and
10 objects and take away all of them. Have him/her say the original total and the new
total. Then, have your child
write a number sentence that shows what the model shows (for example: 4 -
0 = 4).
- One less: Have your child put out between 1 and
11 objects and take one away from them. Have him/her say the original total and the new
total. Then, have your child
write a number sentence that shows what the model shows (for example: 7 -
1 = 6).
- Two less: Have your child put out between 2 and
12 objects and take two away from them. Have him/her say the original total and the new
total. Then, have your child
write a number sentence that shows what the model shows (for example: 11 -
2 = 9).
- Math families: It is VERY important that your child
develops an understanding of the relationship between addition and
subtraction – the idea that subtraction is a reversal of the
addition process, and vice versa.
So, with any of the facts above, we often ask students to write math
families that include
two addition and two subtraction facts with the same three values. It will be most helpful for
students to have concrete objects in front of them to model these facts as
they write them. For example,
if the fact being explored is 5 + 2 = 7, the math family would include 2 +
5 = 7, 7 – 5 = 2, and 7 – 2 = 5. It is also important that your child knows that these
can be written as 7 = 5 + 2, 7 = 2 + 5, 2 = 7 – 5, and 5 = 7 –
2. However, it is often
difficult at first for students to understand this; what often helps is to
help them think of the equal sign meaning is the same as or balances. (7 is the same as 5 + 2, or 7 balances 5 + 2.)
- Doubles (subtraction): Again, have your child model/look for doubles facts (see
above). However, this time, ask
your child to think of subtraction facts that relate the whole set to the
value that is doubled and write a subtraction fact. (Math families – above
– will also help with this.)
For example, if a student models 4 + 4 = 8, it is easy to see that
8 – 4 = 4. Have your
child say this and write the number sentence.
- Make 10: One of the most important
foundational concepts for students at this age is to understand what
numbers can be combined to make 10.
This helps to develop place value understanding and also assists in
mental and paper/pencil computation later on. There are many ways to help students explore these
combinations: One way is to use 2 rows of 5 objects, where some of the
objects are one color and some another color. (Ex: 6 blue and 4 green, so they would say and write 6
+ 4 = 10, 4 + 6 = 10, 10 – 6 = 4, and 10 – 4 = 6.) Similarly, students can use their
10 fingers – hold some up and put some down; then say and write the
matching number facts. When
students have had some of these experiences, you can practice with them
with card games like Tens Go Fish, where you only use cards that have
values of 10 or less, and the goal is to collect pairs of 10. (If a player had a 7, she could
ask the next player for a 3.)
Even in the car, you can say numbers and have your child tell you
what numbers go with them to make 10 (ex: you say 2; child says 8).
Click here for a
Microsoft Word document that lists many fun ways to practice facts once
students have learned them. See below for some websites that provide fluency practice.
Other helpful activities for grade 1, any time, any place:
- How much is needed to
get the next ten? Give your child a number between 0 and
100, and ask how much is needed to get to the next (multiple of) ten. For instance, if you said 7, your
child would say 3. If you
said 82, your child would say 8.
This is a very helpful element of developing mental computation
skills. Most children will
have to start with relatively low numbers. An appropriate extension for grade 1 would be to ask
how much is needed to get to 100.
- What is 10 more? 10 less? 20 more?
30 less? Give your child a number
between 0 and 100, and ask what number would be 10 more than that number (or
10 less, or 20 less, or 50 more, or any multiple of 10 more or less). This is a great place value
activity and also helpful in developing mental computation skills. Most children will have to start
with 10 more and 10 less and later work up to higher values. An appropriate extension for grade
1 would be to ask about (for instance) 15 more, 21 less, etc. This activity can also be done in
the context of money (what is 10 cents more?).
Grade 2
By
the end of second grade, the state of Ohio expects that students are fluent
with the addition and subtraction facts to 10 + 10 and 20 – 10. Along with the strategies listed above
for first grade, we use the strategies below to
help students reach this goal.
- Near doubles: A near doubles fact is a fact that is
one away from a doubles fact.
For instance, 4 + 5 = 9 (along with 5 + 4 = 9, 9 – 5 = 4, and
9 – 4 = 5.) It is VERY
helpful for students to connect these directly to the doubles facts
instead of learning them separately.
One way to help your child explore these facts is to have him/her
model a doubles fact, such as 5 + 5 = 10, with concrete objects; then,
either add 1 to one set of 5 or take 1 away. Then, your child should say out loud what the new model
shows and write the addition and subtraction facts that relate to the
model (like the four above).
- Two apart facts: We can either think of these facts as
two away from a double, or one up and one down from a double. An example of a two apart fact is
5 + 7 = 12 (along with 7 + 5 = 12, 12 – 5 = 7, and 12 – 7 =
5). For this example, we
could start by asking a child to model 5 + 5, add 2 to one set of 5; then
say out loud and write the four related addition and subtraction facts. OR, we could ask the child to
model 7 + 7, take 2 away from one set of 7; then say and write the four
facts. OR, we could ask the
child to model 6 + 6, take 1 from one set of 6 and put it with the other
set; then say and write the four facts. For the best chance of making solid connections in the
mind of the child, it is best to do ALL of these at various times.
- Using 10 as a landmark: This strategy helps to learn most of
the facts that might be most challenging for students to remember. (The Make 10 strategy above in
first grade is an important precursor to this.) Concrete objects and the number line are helpful models
for this strategy. An example
fact in this set could be 5 + 8 = 13. There are many ways to think about this fact, but using
a concrete model with this strategy could involve setting up two 10-frames
(each with two rows of 5 empty spaces). Have your child fill in 5 of the spaces in one frame
with objects; then remind him/her that 8 need to be added. Have your child fill the frame the
rest of the way – using 5 objects – then place the final 3 in
the second frame. This is a
very visual way to help the student use 10 as a landmark to find
the sum. Again, the child
should then say and write 5 + 8 = 13. (8 + 5 can also be modeled in the same way.) It is easy to model the reverse
subtraction problem with this model also – in the example 13 - 8,
start with 13, take away 3 to get to 10, then take away 5 more to get
5. Then write and say the
fact 13 – 8 = 5. (13
– 5 can also be modeled in the same way.) Going through this process may seem time-consuming, but
it will help your child to firmly establish 10 as an important value in
thinking about many types of arithmetic problems.
Click here for a Microsoft Word
document that lists many fun ways to practice facts once students have learned
them. See below
for some websites that provide fluency practice.
Also,
by the end of second grade, the state of Ohio expects that students are learning
strategies for double-digit addition and subtraction. Fluency is not expected until the end of grade 3. Both through student-generated
strategies and teacher facilitation, we encourage the following types of
strategies (these are examples and should not be considered a complete
list). Many of these strategies
are easy to use mentally. The
names/descriptions of each strategy are provided for adult reference only.
For addition:
- To add 45 + 39: 44 + 40 = 84
(this is called compensation
since 1 was added to 39 and taken from 45)
- To add 38 + 71: 40 + 69 = 109
(another example of compensation since 2 was added to 38 and taken from 71)
- Add tens; then add ones: 57 + 38
= 50 + 30 + 7 + 8 = 80 + 15 = 95 (students often do this naturally
before any instruction)
- Add tens; then add ones from first
addend; then add ones from second addend: 94 + 38 = 90 + 30 + 4
+ 8 = 120 + 4 + 8 = 124 + 8 = 132)
For subtraction:
- To subtract 83 – 19: 84
– 20 = 64 (this is also compensation since 1 was added to both 83 and 19
– the difference will still be the same)
- To subtract 50 – 22 = 48
– 20 = 28 (this is also compensation since 2 was subtracted from both 50
and 22 – the difference will still be the same)
- Subtract tens of smaller number, then
subtract ones – to find 52 – 37: 52 – 30 = 22; 22
– 7 = 15
- Count up to subtract – to find
134 – 58: 58 to 60 is 2; 60 to 130 is 70; 130 to
134 is 4; the total is 76) – this strategy really
emphasize the difference or distance between the two numbers (visualize
this on a number line)
Other helpful activities for grade 2, any time, any place:
- How much is needed to
get to 100? Give your child a number between 0 and 100, and ask how
much is needed to get to 100.
For instance, if you said 35, your child would say 65. If you said 71, your child would
say 29. This is a very
helpful element of developing mental computation skills. Most children will have to start
with multiples of 5 and 10, but work in school on the 100 chart will help
them start with other numbers also.
An appropriate extension for grade 2 would be to start at numbers
between 100 and 200 and ask how much is needed to get to 200.
- What is 10 more? 10 less? 20 more?
30 less? Give your child a number
between 0 and 100, and ask what number would be 10 more than that number
(or 10 less, or 20 less, or 50 more, or any multiple of 10 more or
less). This is a great place
value activity and also helpful in developing mental computation skills. Most children will have to start
with 10 more and 10 less and later work up to higher values. An appropriate extension for grade
2 would be to start at numbers between 100 and 200 and ask the same types
of questions. This activity
can also be done in the context of money (what is 10 cents more?).
Grade 3
Grade
3 is a challenging year for students in terms of the Ohio standards. During this year, students are expected
to learn the following:
·
Fluency
in multiplication and division facts (to 10 x 10 and 100 divided by 10)
·
Fluency
in two- and three-digit addition and subtraction
·
Fluency
in multiplying and dividing double- and triple-digit numbers by single digit
numbers
And
these are just three of the twelve indicators in the Number standard –
along with indicators in Measurement, Geometry, Algebra, and Data!
For multiplication and division facts (listed in the order that
generally makes sense for most students and that we use as part of the fluency
plan):
It is
important that students model and describe these facts concretely before the
notation is introduced, and when notation is introduced, students should be
able to verbalize that we are finding groups of a given value (multiplication)
or how many groups of one value are in another (division). The symbol / is used below for the
division sign because not all web browsers can read the division sign as a
symbol.
- Doubles: These facts relate to the doubles
addition facts (see grade 1 above) because we are multiplying by 2. For instance, 7 x 2 = 14. Have your child put out 7 objects
and then 7 more (in rows), say 2 groups of 7 is 14, and write 2 x 7 = 14. Then, have your child model 7
groups of 2 (in rows), say 7 groups of 2 is 14, and write 7 x 2 = 14. Ask your child what is the same
and different about these two facts – we are now looking at the commutative
property since the values can be multiplied in either order (as in
addition). At this point, it
is a good idea to bring in the two related division facts as well. You can do this by asking how many
groups of 2 are in 14 (child should say 7) and then having your child
write 14 / 2 = 7. Similarly,
how many groups of 7 are in 14?
(2) The child should
say this and write 14 / 7 = 2.
- Tens: Tens facts tend to be easy for
students to remember, but it is important that they learn them with
understanding. For instance,
your child can use a 10 by 10 grid to model (shade) 3 groups of 10 and
find that this is 30; then say this and write 3 x 10 = 30. Doing this with several other
numbers will make the point that we can simply append a 0 to the original value to find the
product of 10 and that value.
(It is not a great idea to say add a 0 because we are not, in fact, adding 0
to the number, and though this makes sense to an adult, it may not make
sense to a child who is just learning this idea.) Then, ask your child what 10
groups of 3 would equal (using the grid to check if needed), and have your
child write 10 x 3 = 30.
Next, ask how many groups of 10 are in 30, and have your child say
this and write 30 / 10 = 3.
Similarly, how many groups of 3 are in 30? (10) The child should say this and write 30 / 3 = 10.
- Zeros: Learning the zeros multiplication
facts is not difficult, especially when a child can think about them
concretely. How many are in 0
groups of 8? 0 groups of 5? 9 groups of 0? 2 groups of 0? For each, have your child say this
statement, the product (0), and write the fact, such as 0 x 8 = 0 or 9 x 0
= 0. Be aware that children
do tend to confuse these, when not thinking, with the zeros addition
facts. For division, we have
to be cautious. We can ask
how many groups of 8 are in 0, or how many groups of 4 are in 0, etc. These would be written as 0 / 8 =
0 or 0 / 4 = 0. However, we
cannot divide BY 0! For
example, 6 / 0 = ? This would
be like asking how many groups of 0 are in 6; there is no reasonable
answer. Another way to look
at this: if there were an answer (a quotient) in this problem, we could
work backwards and say that that answer times 0 would equal 6. Impossible! So, do not present your child with
questions like 5 / 0 = __.
- Ones: Again, usually these are not difficult
for students, but sometimes they will confuse them, when not thinking,
with the one more
addition facts. Have your
child model 4 groups of 1, for example, say that 4 groups of 1 is 4, and
write 4 x 1 = 4. Then have
your child model 1 group of 4, and say and write the fact 1 x 4 = 4. For division, ask how many groups
of 1 are in 4, and have your child say this and write 4 / 1 = 4. Then, ask how many groups of 4 are
in 4, and have your child say this and write 4 / 4 = 1.
- Fives: The fives facts should be related to
the tens facts since each product of 5 is half a product of 10 (ex: 6 x 10
= 60; 6 x 5 = 30). A way to
have your child model these is to use 10-frames (2 rows of 5 empty spaces
in each frame) and fill rows of 5.
6 rows of 5 would contain 30 objects. Then, you can ask how many are in 5 groups of 6 (child
may need to model this or may not), and the child can say 5 groups of 6
are 30 and write 5 x 6 = 30.
Ask how many groups of 5 are in 30, and the child can model this
and then say and write 30 / 5 = 6.
Finally, ask how many groups of 6 are in 30, and the child can
model this and then say and write 30 / 6 = 5.
- Nines: The nines facts should also be
related to the tens facts since each product of 9 is a product of 10 minus
one set (ex: 4 x 10 = 40; 4 x 9 = 36). A way to have your child model this is to use 10-frames
(2 rows of 5 empty spaces in each frame) and fill each frame except for
one space. 4 sets of 9 would
contain 36 objects (40 with 4 missing). Your child should say that 4 groups of 10 is 40, so 4
groups of 9 is 36. Then, you
can ask how many are in 9 groups of 4 (child may need to model this or may
not), and the child can say 9 groups of 4 are 36 and write 9 x 4 =
36. Ask how many groups of 9
are in 36, and the child can model this and then say and write 36 / 9 =
4. Finally, ask how many
groups of 4 are in 36, and the child can model this and then say and write
36 / 4 = 9.
- Squares: The squares facts are those where a
value is multiplied by itself and where the model is literally a
square. For instance, 5
groups of 5 is 25, or 5 x 5 = 25.
If a student models this with 5 rows of 5 objects (especially
squares!), he/she will create a figure (an array) that is essentially
square. Have your child model
these and also describe and write the related division facts. In this case, ask how many groups
of 5 are in 25, and have the child say this (and the quotient – the
answer) and write 25 / 5 = 5.
- Doubles and one more
set (threes): The
threes facts should be related to the doubles facts since each product of
3 is a product of 2 plus one more set (ex: 8 x 2 = 16; 8 x 3 = 24). A way to have your child model
this example is to lay out 8 rows of 2; then add a third object to each
row. Then, your child should
say that 8 groups of 2 is 16, so 8 groups of 3 is 24 (16 + 8), and he/she
should write 8 x 3 = 24.
Then, you can ask how many are in 3 groups of 8 (child may need to
model this or may not), and the child can say 3 groups of 8 are 24 and
write 3 x 8 = 24. Ask how
many groups of 3 are in 24, and the child can model this and then say and
write 24 / 3 = 8. Finally,
ask how many groups of 8 are in 24, and the child can model this and then
say and write 24 / 8 = 3.
- Which are Left? Facts: The only multiplication facts that are
not covered by the strategies listed above are 4 x 6, 4 x 7, 4 x 8, 6 x 7,
6 x 8, and 7 x 8 (and the related facts such as 6 x 4, 7 x 4, etc.). This does not mean that we should
simply ask students to memorize these facts and the associated division
facts! See grade 4 below for
ways to work on fours facts and two apart multiplication facts, and any of
these facts can be modeled with concrete objects and related to other
facts. For example, sevens
facts can be related to fives and twos: 6 x 7 is the same as 6 x 5 plus 6
x 2 (this can be understood easily with a model). Another example: 7 x 8 is the same
as 7 x 7 plus one more 7.
Always encourage your child to make connections to help recall the
facts.
Click here
for a Microsoft Word document that lists many fun ways to practice facts once
students have learned them. See below for some websites that provide fluency practice.
For fluency in two- and three-digit addition and subtraction
(grade 3):
Along
with the strategies from grade 2 (see above), we
encourage the use of the following strategies. The following are examples and not intended to represent
every possible strategy. Also see
our videos for
demonstrations of many of these strategies. The most important goal is that students should be able to
use numbers flexibly and efficiently to compute accurately because one strategy may be very easy to
use in one problem and not so easy to use in another.
For addition:
- Add hundreds, then tens, then ones
– ex: 735 + 276: 700 + 200 = 900; 30 + 70 = 100; 5 + 6 = 11; 900 + 100 + 11 = 1011
- Add hundreds of second addend to first
addend, then tens, then ones – ex: 258 + 594: 258 + 500 = 758;
758 + 90 = 848; 848 + 4 = 852
- Compensation (works very easily in
some cases) – ex: 258 + 594: 258 + 600 = 858; 858 – 6 = 852
- Standard American algorithm WITH
understanding – ex: 367 + 459:
·
7 + 9 = 16,
record the 6, and add the 1 (10) from 16 to the tens column;
·
1 + 6 + 5
(which really is 10 + 60 + 50) is 12 (which really is 120), record the 2
(20), and add the 1 (100) to the hundreds column;
·
1 + 3 + 4
(which is really 100 + 300 + 400) is 8 (800); answer is 826
For subtraction:
- Subtract hundreds, then tens, then
ones; then combine – ex: 326 – 179: 300 – 100 = 200; 20 – 70 = -50; 6 – 9 = -3; 200 – 50 – 3 = 147
- Find the distance from one value to the
other: ex: 807 – 568: 568 to 600 is 32; 600 to 807 is 207; 207 + 32 = 239
- Compensation (works very easily in
some cases) – ex: 461 – 285: 461 – 300 = 161; 161 + 15 = 176 (since taking away 300
from 461 was 15 too much)
- Standard American algorithm WITH understanding
– ex: 812 – 654:
·
Choose not to
take 4 from 2, so regroup one ten; 12 – 4 = 8;
·
Choose not to
take 5 from 0 (which is really 50 from 0 tens), so regroup one hundred; 10
– 5 = 5 (which is really 100 – 50 = 50);
·
Subtract
hundreds; 7 – 6 = 1 (which is really 700 – 600 = 100);
answer is 158
For fluency in multiplying and
dividing double- and triple-digit numbers by single digit numbers (grade 3):
We
encourage the use of the following strategies, most of which rely on the
distributive property. The
following are examples and not intended to represent every possible
strategy. Also see our videos for demonstrations
of many of these strategies. The most
important goal is that students should be able to use numbers flexibly and efficiently to compute accurately because
one strategy may be very easy to use in one problem and not so easy to use in
another.
For multiplication (several of these can be modeled using the
areas of rectangles; see third strategy below for an example):
- Repeated addition (only to be used initially) – ex: 82 x 4 = 82 + 82 + 82
+ 82 = 328
- Decomposing by tens and ones (also
used initially)
– ex: 37 x 5 = (10 x 5) + (10 x 5) + (10 x 5) + (7 x 5) = 50
+ 50 + 50 + 35 = 185
- Decomposing by place value – ex.
A: 268 x 7 = (200
x 7) + (60 x 7) + (8 x 7) = 1400 + 420 + 56 = 1876; ex. B: 48 x 9 = (48 x 10) – 48
= 480 – 48 = 432
·
Sketch a
rectangle with sides 268 and 7 units; divide this into three rectangles: 200 by
7, 60 x 7, 8 x 7; find the area of each; add these areas
- Other partitions – ex: 527 x 4 =
(500 x 4) + (25 x 4) + (2 x 4) = 2000 + 100 + 8 = 2108
- Standard American algorithm WITH
understanding – ex: 273 x 8:
·
3 x 8 = 24;
record the 4; regroup the 2 (really 20);
·
7 x 8 = 56
(really 70 x 8 = 560); 56 + 2 = 58 (really 560 + 20 = 580); record the 8
(really 80); regroup the 5 (really 500);
·
2 x 8 = 16
(really 200 x 8 = 1600); 16 + 5 = 21 (really 1600 + 500 = 2100); answer
is 2184
For division (the symbol / is used below for the division sign because not all
web browsers can read the division sign as a symbol):
- Use multiplication/building up –
ex: 213 / 8 (How many groups of 8 are in 213?)
·
8 x 20 = 160; 8 x 5 = 40; 160 + 40 = 200;
·
8 x 1 = 8; 200 + 8 = 208;
·
20 + 5
+ 1 = 26; so,
26 groups of 8 with 5 left over
- Take out multiples of 10 of the
divisor – ex: 152 / 6 (How many groups of 6 are in 152?)
·
152 –
60 = 92 (took out 10
groups of 6);
·
92 – 60
= 32 (took out 10 more groups
of 6);
·
32 – 30
= 2 (took out 5 more
groups of 6);
·
10 + 10 +
5 = 25; so, 25 groups of 6
with 2 left
- Modified standard American algorithm
– ex: 597 / 8 (How many groups of 8 are in 597?) - *Since this is
difficult to display as a graphic on a webpage so that all web browsers
can interpret it, you may want to jot down the problem in the standard
format and follow along with the steps as described below.
·
Think: How
many times does 8 go into 590?
(70) Write 70 above the
division sign; subtract 560 from 597 to get 37.
·
Think: How
many times does 8 go into 37?
(4) Write + 4 after the 70
above the division sign; subtract 32 from 37 to get 5.
·
The answer is
74 with 5 left over.
- Standard American algorithm WITH
understanding – ex: 314 / 7 (How many groups of 7 are in 314?) -
*Since this is difficult to display as a graphic on a webpage so that all
web browsers can interpret it, you may want to jot down the problem and
follow along with the steps as described below.
·
Think: How
many times does 7 go into 310 (since it cannot go into 3 evenly)? 40 – record the 4 above the 1 (in
the tens place to indicate 40), and write 280 below 314 (instead of just 28)
since 7 x 40 = 280.
·
Subtract: 314
– 280 = 34.
·
Think: How
many times does 7 go into 34? 4
– record the 4 above the 4 in 314, and write 28 below 34 since 7 x 4 =
28.
·
Subtract: 34
– 28 = 6. The answer is 44
with 6 left over.
Other helpful activities for grade 3, any time, any place:
- How much is needed to
get to the next multiple of 100? Give your child a number between 0 and
1000, and ask how much is needed to get to the next multiple of 100. For instance, if you said 342,
your child would say 58. If
you said 210, your child would say 90. This is a very helpful element of developing mental computation
skills. Most children will
have to start with multiples of 5 and 10, and some may need to start with
numbers less than 100, but playing the game Close to 100 will help them
start with other numbers also.
An appropriate extension for grade 3 would be to ask how much is
needed to get to 1000.
- What is 10 more? 10 less? 20 more?
30 less? 100
more? 400 less? Give
your child a number between 0 and 1000, and ask what number would be 10
more than that number (or 10 less, or 20 less, or 50 more, or 100 more, or
200 less, or any multiple of 10 or 100 more or less). This is a great place value
activity and also helpful in developing mental computation skills. With three-digit numbers, most
children will have to start with 100 more and 100 less and later work up
to higher values and 10 more/less (it is a bit harder to find 10 more/less
when the numbers are in the hundreds since children tend to focus on the
hundreds). An appropriate
extension for grade 3 would be to ask about (for instance) 150 more, 220
less, etc. This activity can
also be done in the context of money (what is 50 cents more?).
Grade 4
Grade
4 is the last year in the Ohio standards that includes whole number
computation. During this year,
students are expected to learn the following:
·
Fluency
in multi-digit addition and subtraction
·
Fluency
in multiplying and dividing by double-digit numbers and multiples of 10
We also review multiplication and division facts in fourth grade. Along with reviewing some of the
strategies developed in grade 3 above, we develop the
following strategies in grade 4. (The symbol / is used below for the
division sign because not all web browsers can read the division sign as a
symbol.)
- Squares and one more
set: In this set of
facts, each product is a square plus one more set of the number being
squared (ex: 5 x 5 = 25 which is 5 sets of 5; 5 x 6 = 30 which is 5 sets
of 6, or 6 sets of 5). A way
to have your child model this example is to lay out 5 rows of 5; then add
a sixth object to each row.
Then, your child should say that 5 groups of 5 is 25, so 5 groups
of 6 is 30 (25 + 5), and he/she should write 5 x 6 = 30. Then, you can ask how many are in
6 groups of 5 (child may need to model this or may not), and the child can
say 6 groups of 5 are 30 and write 6 x 5 = 30. Ask how many groups of 5 are in 30, and the child can
model this and then say and write 30 / 5 = 6. Finally, ask how many groups of 6 are in 30, and the
child can model this and then say and write 30 / 6 = 5.
- Doubles doubled
(fours): The fours
facts should be related to the doubles facts since each product of 4 is
twice a product of 2 (ex: 3 x 2 = 6; 3 x 4 = 12). A way to have your child model
this example is to lay out 3 rows of 2; then double the size of the model
(3 rows of 4). Then, your
child should say that 3 groups of 2 is 6, so 3 groups of 4 is 12 (6 x 2),
and he/she should write 3 x 4 = 12.
Then, you can ask how many are in 4 groups of 3 (child may need to
model this or may not), and the child can say 4 groups of 3 are 12 and
write 4 x 3 = 12. Ask how
many groups of 4 are in 12, and the child can model this and then say and
write 12 / 4 = 3. Finally,
ask how many groups of 3 are in 12, and the child can model this and then
say and write 12 / 3 = 4.
- Two apart
multiplication facts:
The two apart multiplication facts should be related to the squares facts
since each two apart fact is the square of the number in between the
factors, minus 1 (ex: 7 x 7 = 49; 6 x 8 = 48, or 49 - 1). In this case, 6 x 8 is the two
apart fact. A way to have
your child model this example is to lay out 7 rows of 7; then take one
away from the corner and move the rest in that column down to create an
eighth row. Then, your child
should say that 7 groups of 7 is 49, so 6 groups of 8 is 48 (49 - 1), and
he/she should write 6 x 8 = 48.
Then, you can ask how many are in 8 groups of 6 (child may need to
model this or may not), and the child can say 8 groups of 6 are 48 and
write 8 x 6 = 48. Ask how
many groups of 6 are in 48, and the child can model this and then say and
write 48 / 6 = 8. Finally,
ask how many groups of 8 are in 48, and the child can model this and then
say and write 48 / 8 = 6.
Click here for a Microsoft Word
document that lists many fun ways to practice facts once students have learned
them. See below
for some websites that provide fluency practice.
For fluency in multi-digit addition and subtraction (grade 4):
The following
are extensions of the strategies from grade 3 (see
above). These are examples and
not intended to represent every possible strategy. Also see our videos for demonstrations
of many of these strategies. The
most important goal is that students should be able to use numbers flexibly and efficiently to compute accurately because
one strategy may be very easy to use in one problem and not so easy to use in
another.
For addition:
- Add thousands, then hundreds, then
tens, then ones – ex: 2478 + 1356: 2000 + 1000 = 3000; 400 + 300 = 700; 70 + 50 = 120; 8 + 6 = 14; 3000 + 700 + 120 + 14 = 3834
- Add thousands of second addend to
first addend, then hundreds; then tens, then ones – ex: 4702 + 3859:
4702 + 3000 = 7702; 7702 + 800 = 8502; 8502 + 50 = 8552;
8552 + 9 = 8561
- Compensation (works very easily in
some cases) – ex: 3567 + 1997: 3567 + 2000 = 5567; 5567 – 3 = 5564
- Standard American algorithm WITH
understanding – ex: 2468 + 5967:
·
8 + 7 = 15,
record the 5, and add the 1 (10) from 15 to the tens column;
·
1 + 6 + 6
(which really is 10 + 60 + 60) is 13 (which really is 130), record the 3
(30), and add the 1 (100) to the hundreds column;
·
1 + 4 + 9
(which is really 100 + 400 + 900) is 14 (which really is 1400); record
the 4 (400), and add the 1 (1000) to the thousands column;
·
1 + 2 + 5
(which is really 1000 + 2000 + 5000) is 8 (which really is 8000); answer
is 8435
For subtraction:
- Subtract thousands, then hundreds,
then tens, then ones; then combine – ex: 6394 - 2876: 6000
– 2000 = 4000; 300 – 800 = -500; 90 – 70 = 20; 4 – 6 = -2; 4000 - 500 + 20 – 2 = 3518
- Find the distance from one value to
the other: ex: 3760 – 2831: 2831 to 2900 is 69; 2900 to 3760 is 860; 860 + 69 = 929
- Compensation (works very easily in
some cases) – ex: 8357 – 3989: 8357 – 4000 = 4357; 4357 + 11 = 4368 (since taking away 4000
from 8357 was 11 too much)
- Standard American algorithm WITH
understanding – ex: 8123 - 6579:
·
Choose not to
take 9 from 3, so regroup one ten; 13 – 9 = 4;
·
Choose not to
take 7 from 1 (which is really 70 from 10), so regroup one hundred; 11
– 7 = 4 (which is really 110 – 70 = 40);
·
Choose not to
take 5 from 0 (which is really 500 from 0 hundreds), so regroup one thousand; 10
– 5 = 5 (which is really 1000 – 500 = 500);
·
Subtract
hundreds; 7 – 6 = 1 (which is really 7000 – 6000 = 1000);
answer is 1544
For fluency in multiplying and dividing by double-digit numbers
and multiples of 10 (grade 4):
The
following are extensions of the strategies from grade 3,
most of which rely on the distributive property. These are examples and not intended to represent every
possible strategy. Also see our videos for demonstrations
of many of these strategies. The
most important goal is that students should be able to use numbers flexibly and efficiently to compute accurately because
one strategy may be very easy to use in one problem and not so easy to use in
another.
For multiplication (several of these can be modeled using the
areas of rectangles; see third strategy below for an example):
- Repeated addition (only to be used initially) – ex: 65 x 12 = 130 x 6 = 130
+ 130 + 130 + 130 + 130 + 130 = 780
- Decomposing by tens and ones (also
used initially)
– ex: 27 x 53 = (10 x 53) + (10 x 53) + (7 x 53) = 530 +
530 + 371 = 1431
- Decomposing by place value – ex.
A: 57 x 82 = (50
x 82) + (7 x 82) = (50 x 80) + (50 x 2) + (7 x 80) +
(7 x 2) = 4000 + 100 + 560 + 14 = 4674
·
Sketch a
rectangle with sides 268 and 7 units; divide this into three rectangles: 200 by
7, 60 x 7, 8 x 7; find the area of each; add these areas
- Other partitions – ex: 94 x 45 =
(100 x 45) - (6 x 45) = 4500 - 270 = 4230
- Standard American algorithm WITH
understanding – ex: 35 x 78:
·
5 x 8 = 40;
record the 0; regroup the 4 (really 40);
·
3 x 8 = 24
(really 30 x 8 = 240); 24 + 4 = 28 (really 240 + 40 = 280); record the
28 (really 280);
·
5 x 7 = 35
(really 5 x 70 = 350); record the 50; regroup the 3 (really 300);
·
3 x 7 = 21
(really 30 x 70 = 2100); 21 + 3 = 24 (really 2100 + 300 = 2400); record
the 24 (really 2400);
·
Add: 280 +
2450 = 2730
- Multiplying by larger multiples of 10
(such as 300, 1900, etc.): We want students to recognize that multiplying
by 300, for instance, is the same as multiplying by 3 and then by
100. In order to do this,
they must understand the pattern that when we multiply a whole number by 100, we include 2 extra
zeros at the end of it. (ex:
5 x 100 = 500; 9 x 100 = 900)
So, to multiply by 300, we would use any of the strategies above to
multiply by 3 and then multiply that answer by 100.
For division (the symbol / is used below for the division sign because not all
web browsers can read the division sign as a symbol):
- Use multiplication/building up –
ex: 1263 / 37 (How many groups of 37 are in 1263?)
·
37 x 10 = 370; 370 + 370 = 740 (20 groups of 37 so far);
·
740 + 370
= 1110 (30 groups
of 37 so far);
·
37 x 2 = 74; 1110 + 74 = 1184 (32 groups of 37 so far);
·
1184 + 74
= 1258 (34 groups
of 37 so far)
·
1263
– 1258 = 5; so, the answer is 34 groups of 37 with 5 left over
- Take out multiples of 10 of the
divisor – ex: 2643 / 81 (How many groups of 81 are in 2643?)
·
2643 –
810 = 1833 (took out 10
groups of 81);
·
1833 –
810 = 1023 (took out 10
more groups of 81);
·
1023 –
810 = 213 (took out 10
more groups of 81);
·
213 –
162 = 51 (took out 2
more groups of 81);
·
10 + 10 +
10 + 2 = 32; so, 32 groups of 81 with 51 left
- Modified standard American algorithm
– ex: 5961 / 28 (How many groups of 28 are in 5961?) - *Since this
is difficult to display as a graphic on a webpage so that all web browsers
can interpret it, you may want to jot down the problem in the standard
format and follow along with the steps as described below.
·
Think: How
many times does 28 go into 5900?
(200) Write 200 above the
division sign; subtract 5600 from 5961 to get 361.
·
Think: How
many times does 28 go into 361?
(at least 10) Write + 10
after the 200 above the division sign; subtract 280 from 361 to get 81.
·
Think: How
many times does 28 go into 81? (2)
Write + 2 after the + 10 above the division sign; subtract 56 from 81 to
get 25.
·
The answer is
212 (200 + 10 + 2) with 25 left over.
- Standard American algorithm WITH
understanding – ex: 3792 / 41 (How many groups of 41 are in 3792?) -
*Since this is difficult to display as a graphic on a webpage so that all
web browsers can interpret it, you may want to jot down the problem and
follow along with the steps as described below.
·
Think: How
many times does 41 go into 379 (since it cannot go into 37 evenly)? 90 – record the 9 above the 9 (in
the tens place to indicate 90), and write 3690 below 3792 (instead of just 369)
since 41 x 90 = 3690.
·
Subtract:
3792 – 3690 = 102.
·
Think: How
many times does 41 go into 102? 2
– record the 2 above the 2 in 3792, and write 82 below 102 since 41 x 2 =
84.
·
Subtract: 102
– 82 = 20. The answer is 92
with 20 left over.
- Dividing by larger multiples of 10
(such as 400, 1200, etc.): We want students to recognize that dividing by
400, for instance, is the same as dividing by 4 and then by 100. In order to do this, they must
understand the pattern that when we divide a whole number by 100, we take
away two zeros at the end of it (or move the decimal point two places to
the left, but this is rarely needed in grade 4). (ex: 600 / 100 = 6; 2400 / 100 = 24) So, to divide by 400, we would use
any of the strategies above to divide by 4 and then divide that answer by
100.
Other helpful activities for grade 4,
any time, any place:
- How much is needed to
get to 1000? Give your child a number between 0 and
1000, and ask how much is needed to get to 1000. For instance, if you said 610, your child would say
390. If you said 513, your
child would say 487. This is
a very helpful element of developing mental computation skills. Most children will have to start
with multiples of 100, 10, or 5, but playing the game Close to 1000 will
help them start with other numbers also. An appropriate extension for grade 4 would be to start
between 0 and 10,000 ask how much is needed to get to the next multiple of
1000.
- What is 10 more? 10 less? 20 more?
30 less? 100
more? 400 less? 1000 more? 3000 less? Give
your child a number between 0 and 1000, and ask what number would be 10
more than that number (or 10 less, or 20 less, or 50 more, or 100 more, or
200 less, or 1000 more, or 4000 less, or any multiple of 10, 100, or 1000
more or less). This is a
great place value activity and also helpful in developing mental
computation skills. With
four-digit numbers, most children will have to start with 1000 more and
1000 less and later work up to higher values and 10 or 100 more/less (it
is a bit harder to find 10 or 100 more/less when the numbers are in the
thousands since children tend to focus on the thousands). An appropriate extension for grade
4 would be to ask about (for instance) 2500 more, 4100 less, etc. This activity can also be done in
the context of money (what is $1.50 cents more?).
Grade 5
The fluency activities for grades 5 and 6 primarily relate to
whole number theory and fractions/decimals/percents. We develop the following strategies and skills with students
in grade 5. Many of these are good
activities for any time, any place; also see the activities for grade 4 (any
time, any place) immediately above.
Whole number theory:
- Identifying square
numbers and square roots: A square number is the product
of a number, the square root, multiplied by itself; square numbers
can be represented by a square with the square root being the side length
– 25 (5 x 5), 100 (10 x 10), 16 (4 x 4), 49 (7 x 7), etc.
- Identifying prime and
composite numbers: Prime numbers have exactly two
factors, themselves and 1 (7, 19, 2, 43, etc.). That is, only these two values divide into the number
evenly. Composite numbers
have more than two factors (32, 75, 10, 8, 26, etc.). That is, more than two values
divide into any composite number evenly.
- Order of operations: When simplifying an expression, we simplify in the
following order (moving from left to right within each of these four
steps): anything in parentheses, any exponents, any multiplication or
division, any addition or subtraction – example: 5 + (6 –
3) x 2 = 5 + 3 x 2 = 5 + 6 = 11
See grade 3 and grade 4
above for strategies we use for developing multiplication and division facts
with students. Click here for a Microsoft Word document that lists
many fun ways to practice basic facts once students have learned them. See below for
some websites that provide fluency practice.
Fractions/decimals/percents:
- Benchmark percents: To find 10% of a number, divide it by
10 (since there are ten 10s in 100); to find 25% of a number, divide it by
4 (since there are four 25s in 100); to find 1% of a number, divide it by
100 (since there are one hundred 1s in 100).
- Equivalent fractions
and percents: Students should understand and commit
to memory common equivalents like 1/5 = 20%, 1/3 = 33 1/3%, 3/4 = 75%, and
so on; one way to find the percent from the fraction is to divide the
numerator by the denominator and multiply by 100.
- Rounding decimals: Students may be asked to round to the
nearest tenth, hundredth, or thousandth; look at the decimal place to the
right and round up if 5 or above; examples: (to tenths) 3.467 becomes 3.5;
(to hundredths) 71.243 becomes 71.24; (to thousandths) 8.34178 becomes
8.342.
- Comparing decimals: To compare decimals, they must be
compared place for place from left to right; for example, 2.3 is larger
than 2.165 even though 2.165 appears larger – compare 2 to 2
(equal), 3 to 1 (this is how we know 2.3 is larger); we could go further
if needed. Another example:
50.6 is larger than 5.06 because we compare the 5 in 50.6 to nothing in
the tens place in 5.06.
Grade 6
The fluency activities for grades 5 and 6 primarily relate to
whole number theory and fractions/decimals/percents. We develop the following strategies and skills with students
in grade 6, along with reviewing those from grade 5
above. Several of these (from
grades 5 and 6) are good activities for any time, any place; also see the
activities for grade 4 (any time, any place).
Whole number theory:
- Prime factorization: Breaking a number into prime factors:
75 = 3 x 5 x 5 or 3 x 52;
80 = 2 x 2 x 2 x 2 x 5 or 24 x 5. A prime number is only evenly divisible by itself and
1.
- Greatest common factor
(GCF): The largest
number that is a factor of (evenly divides into) two or more given
numbers; the GCF of 30 and 45 is 15 because no larger number fits evenly
into both.
- Least common multiple
(LCM): The smallest
number that is a multiple of two or more given numbers; the LCM of 4, 9,
and 12 is 36 because they all can be multiplied by another number to get
36.
See grade 3 and grade 4
above for strategies we use for developing multiplication and division facts
with students. Click here for a Microsoft Word document that lists
many fun ways to practice basic facts once students have learned them. See below for
some websites that provide fluency practice.
Fraction, decimal, percent operations:
Please refer to
resources from the textbook, class notes, and the sixth grade homework help
website for help with these operations.
Some websites that can provide
fluency practice (Stow-Munroe Falls City Schools assumes no responsibility for
the content of these sites or links from them):
http://www.mathfactcafe.com
http://www.math.com
http://www.harcourtschool.com/menus/math2002/na/menu_na.html
http://www.funbrain.com
http://www.bbc.co.uk/education/mathsfile/gameswheel.html
http://www.bbc.co.uk/schools/ks2bitesize/maths/
http://www.aplusmath.com/
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