How many positive divisors do 48 and 156 have in common?
I need to find the common divisors of 48 and 156, so I should factor both numbers into their prime factors. 48 = 2^4 * 3, and 156 = 2^2 * 3 * 13. To find the common divisors, I can take any combination of the common prime factors, which are 2^2 and 3. So the common divisors are 1, 2, 4, 3, 6, and 12, which is 6 divisors in total. 