168, 28

84/56 = 1 remainder 28

56/28 = 2 remainder 0

The greatest common factor is

56 = 28*2

84 = 28*3

The least common multiple is 2*28*3 =

56/28 = 2 remainder 0

The greatest common factor is

**28**.56 = 28*2

84 = 28*3

The least common multiple is 2*28*3 =

**168**.