Factor pairs and common multiples

Answer: 12

1. List the factors of both numbers.
2. The largest shared factor is 12:60=5×12 and 72=6×12.

Answer: 90

1. Common multiples are multiples of 30.
2. The first one greater than 69 is 90.

Answer: 7

1. List the factors of both numbers.
2. The largest shared factor is 7:14=2×7 and 21=3×7.