Question

Use the method of dividing by prime factors to find the greatest common factor of 140 and 350.

Answer 1

140 = 2*2*5*7

350 = 2*5*5*7

now, let's notice, the 2, 5 and 7 are repeated on both, so we'll use them once, and then we add the non-repeated part to it to get the GCF.

(2*5*7)*2*5  <----- that's the GCF ------> 700.