Question

How do you list all the factors of 70?

Answer 1

List in their pairs

1 & 70
2 & 35
5 & 14
7 & 10

I don't need to check between the numbers 10, 14, 35 and 70 because I have the factors in pairs.

Answer 2

Another way is to use prime factors

`70=2xx5xx7`

2 and 35, 5 and 14, 7 and 10 plus 1 and 70

Answer 3

`1,2,5,7,10,14,35,70`

Explanation:

Write a number as the product of its prime factors.

`70 = 2xx5xx7`

`1` is a factor of all numbers.

Find all the factors by grouping the factors:

One at a time:

`1, 2, 5, 7`

Two at a time:

`2xx5=10," "2xx7=14" "5xx7 =35`

Three at a time:

`2xx5xx7 =70`

The eight factors of `70` are:

`1,2,5,7,10,14,35,70`