Question

How do you find the GCF of 35 and 65?

Answer 1

See explanation.

Explanation:

To find the `GCF` of 2 numbers you have to do the prime decomposition of both numbers (write both numbers as a product of prime numbers or their powers)

`35=5xx7`

`65=5xx13`

The greatest common factor `GCF` is a product of all prime numbers which occur in both products. Here only a number `5` appears in both products, so

`GCF(35,65)=5`

Answer 2

A tip!

Explanation:

If the last digit (rightmost) is a 0 or a 5 then the whole number is divisible by 5.