The sum of three different numbers is 18 if every number is a prime number what are the three numbers

First we should look at the prime numbers (numbers that can only be divded by itself and one)
1,2,3,5,7,11,13,17
Now it can't be 17 because 18-17=1, and you need one more number
It can be 13, because 18-13=5, and 5-3=2, meaning the numbers can be 2, 3, and 13
It can be 11, because 18-11=7, and 7-5=2, meaning the numbers can be 2,5, and 11

Idon't know the answer