The sum of three prime numbers is 12. what could the numbers be?

Prime numbers are numbers that have factors which are only 1 and itself.

So, for the sum of 3 prime number to equal 12; those prime numbers would have to be the following:

3
7
2

7 + 3 = 10
10 + 2 = 12

Yes. 2 is actually a prime number. It's only factors are 1 and itself. Which does contradict popular belief as most people think all even numbers are not prime.

Hope this helped ;)