Question

What is i hcf of 21 and 28

Answer 1

The factors of 21 are 1, 3, 7, and 21 .

The factors of 28 are 1, 2, 4, 7, 14, and 28 .

The factors common to both numbers are 1 and 7 .

The greatest one is 7.

Answer 2

`21|3 \\ 7 \ |7 \\ 1 \\\\ 21=3*7 \\\\ 28|2 \\ 14|2 \\ 7 \ |7 \\ 1 \\\\ 28=2^2*7 \\\\ H.C.F(21;28)\to\boxed{7}`