Question

timed problem
score:6/10
find the greatest common factor of 18 and 42.
answer
6
21
1
2

Explanation:

Step1: List prime factors of 18

$18 = 2 \times 3 \times 3$

Step2: List prime factors of 42

$42 = 2 \times 3 \times 7$

Step3: Multiply common prime factors

$\text{GCF} = 2 \times 3 = 6$

Answer:

6