Question

What is the highest common factor of 42 and 390

Answer 1

GCF = 6

Explanation:

Factors of 42 are: 1,2,6,7,21, and 42

Factors of 390 are: 1,2,3,5,6,10,13,15,26,30,39,65…….

The common factors are 1, 2, 3, and 6

Answer 2

Explanation:

Using prime factorization:

42 = 2 x 3 x 7

390 = 2 x 3 x 5 x 13

2x 3 = 6 = HCF