Question

Find the Greatest common factor of 4,42, and 14

Answer 1

Factor each number into its prime factors

4 = 2*2

42 = 2*3*7

14 = 2*7

The value "2" shows up exactly one time for each list of factorizations. No other number (not 3, nor 7) shows up for all three factorizations.

Answer: 2

Answer 2

2 is the greatest cmf as
$4 = 2 \times 2 \\ 42 = 2 \times 21 \\ 14 = 2 \times 7$
Thus 2 is the Greatest common factor