Question

How do you find the greatest common factor of `140n, 140m^2, 80m^2`?

Answer 1

Factorize. But you can see at a glance that the letters have no common factor.

Explanation:

So we're left with finding the GCF of `140,140,80`

`140=7xx20and 80=4xx20`

So the GCF `=20` (no common factors between `4` and `7`)

Note:
Of course you could factorize all the way down to the primes:

`140n=2xx2xx5xx7xxn`, etc.