Lesson: Finding Factors of Whole Numbers

Claire is learning how to find factor pairs for numbers. These are pairs of factors with a given product.

She makes arrays from 15 blocks to find the factors of 15.

She sees that 1 and 15 are a factor pair, because their product is 15. What is another factor pair for 15?

Zachary is finding factor pairs of 42. Which number is missing from the table?

Factors of 42
1	42
2	21
3
6	7

Virginia is drawing factor rainbows to show all the factor pairs for 20. She writes the factors in order from smallest to largest and draws an arc between each two factors in a pair.

The green arc shows that 2 and 10 are a factor pair, since .

Now it is your turn. Which of the following is a factor rainbow showing all the factor pairs of 24?

Patrick is finding factor pairs of 45. He has drawn a factor rainbow. The factors are written from smallest to greatest and then the factor pairs are joined up.

Which two numbers are missing?

Which two of these numbers are factors of 46?