What do 16 and 12 both go into?

Answer 1

In terms of prime divisors, 12 equals 2 times 2 times 3. 16 equals 2 times 2 times 2 times 2. So the two numbers divide every number whose prime divisors include four 2's and a 3, the smallest of which is 16 times 3 or 48, and they divide every integer multiple of 48.