The largest positive integer that divides the numbers 16 and 20 is 4.

What is the smallest value of the positive integer nn such that the largest positive integer that divides the numbers n,16, and 20 is also 4?

The smallest n would be 4 itself, because:

GCD{4, 16, 20} = 4, or:

GCD{8, 16, 20} = 4, or:

GCD{12, 16, 20} = 4 and so on......