Wednesday, January 31, 2018

Jan 31, 2018

Homework: Study for Math test.

Some strategies to help you but not limited to

Multiplication Strategies

1) Hands on Materials: Use Montessori materials or other hands-on
materials like blocks to create arrays.
2) Made a Representation: Draw an array on paper to solve, like the
picture on the right. Or draw a model of equal groups.
3) Skip Count: This works especially well with the numbers 2, 3, 4, and 5. For example, to find 5 x 5, skip
count by 5, 5 times/ 5 x 5 = 25.
3) Use Doubling: To use doubling, you would begin with a fact that you know to find a more challenging
fact. For example, if you were trying to find 6 x 4, you could think of 3 x 4= 12. Double one factor and then
you can double the product to get your answer: 6 x 4 = 24. You can use Repeated Doubling as well. If I want
to find 6 x 8, I could find 6 x 2 = 12, double it once to get 6 x 4 = 24, and double it again to get 6 x 6 = 48.
4) Use Known Facts: If you are trying to figure out what 6 x 8 is, and you know 6 x 6, you can use your
knowledge of 6 x 6 = 36 to find 6 x 8 by adding two more groups of 6. 36 + 6 + 6 = 48. You could also work
backwards by using 6 x 6 = 36 to find 6 x 5 but subtracting one group of 6. 6 x 5 = 30. Since 10s are easy to
multiply, this strategy works well for 9s. For example, to find 9 x 9, you could multiple 9 x 10 = 90 and
subtract a 9 which equals 81.

Division Strategies

The following is a list of strategies that you can use to solve 2 digit by 1 digit multiplication problems.
1) Hands on Materials: Use Montessori materials or other hands-on materials like blocks which can be
divided to create equal groups.
2) Made a Representation: Draw an array on paper to solve, like the
picture on the right which solves 12 ÷ 4. Or draw a model of equal groups.

3) Related Multiplication Facts: To find 72 ÷ 8, think 8 times what number is 72? If you know that 8 x 9 =
72, then 72 ÷ 8 = 9.
4) Halving: To find 64 ÷ 4 I could think 64 ÷ 2 = 32, and then divide it by 2 again to get 32 ÷ 2 = 16. I can also
do Repeated Halving. For example, to find 96 ÷ 8 I could first divide 96 by 2 which is 48, and then divide it
by 2 again which is 24, and then divide it by 2 one more time which is 12. Therefore 96 ÷ 8 = 12.
5) Repeated Subtraction: This is kind of like the opposite of skip counting. To find 18 ÷ 6 I can keep
subtracting 6 from 18 until I get to 0. The amount of times I had to subtract 6 is my answer. 18 – 6 = 12 – 6
= 6 – 6 = 0. So 18 ÷ 6 = 3.


Josh Berry
Grade 4/5 Teacher, Beddington Heights
Calgary Board of Education l cbe.ab.ca
t l 403-777-6610

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June 22, 2018