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AB: required BC: required

MB: required ON: recommended

Teacher Resource 6.1 Unit 7 Number Sense pp. H-11–14

New Canadian Edition

JUMP Math™ Copyright © 2018 JUMP Math

NS6-20

A Shorter Way to Find Factors

Students will:

• find factors of numbers up to 100, and determine whether a given one-digit number is a factor of a given whole number in the range 1–100.

AP Book 6.1 pp. 127–128

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Divide.

See p. H-11 for details.

15 ÷ 3

17 ÷ 3

3 × ____ = 15 and 3 × ____= 18

Is 3 a factor of any of these numbers?

Hint: How can you tell from the remainder?

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Exercises:

Is 4 a factor of the number?

a) 18

b) 16

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Is 7 a factor of 364? How can you tell?

7

3 6 4

Review: Long division.

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I want to check whether 3 is a factor of 145.

Is it better to skip count or use long division?

Demonstrate both strategies. See p. H-12 for details.

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See p. H-12 for details.

I want to check whether 3 is a factor of 14.

Should I use skip counting or long division?

What if I want to know whether 3000 is a factor of 14 000?

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Why can I stop at 7?

See p. H-12 for details.

Factors of 28

1

28

2

14

3

x

4

7

5

x

6

x

7

​

8

​

9

​

10

​

11

​

12

​

13

​

14

​

28

​

I made this chart to find the factors of 28.

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We can save time by writing only the numbers that are factors.

First

Factor

Second

Factor

See p. H-13 for details.

1

15

3

5

5

3

15

1

​

​

​

​

First

Factor

Second

Factor

1

12

2

6

3

4

4

3

6

2

12

1

First

Factor

Second

Factor

1

14

2

7

7

2

14

1

​

​

​

​

Examples:

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Exercises:

List all the factor pairs of …

a) 16

Bonus: 24

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Do you notice any patterns in the charts you made?

See p. H-13 for details.

First

Factor

Second

Factor

1

12

2

6

3

4

4

3

6

2

12

1

As soon as we find a number that is already part of a factor pair, we can stop.

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Remember:

You may need to use long division to look for factors.

Hint: When the remainder is 0, the number is a factor.

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Exercises:

Make a chart to find all the factor pairs.

Hint: Stop when you get to a number that is already shown in the chart.

a) 42