Question

What is the greatest cThe work that Yi did to find the greatest common factor of 42 and 63 is shown below.

Factors of 42: 1, 2, 3, 6, 7, 14, 21, 42
Factors of 63: 1, 7, 9, 63

The greatest common factor is 7.

What is Yi’s error?
ommon factor of 20 and 36?

Answer 1

Yi forgot two factors of 63, which are 3 and 21.

This would make the greatest common factor 21.