After I solved the problem, I want to check other’s good solutions.
I have question after I read this solution.
First, I understood the logic of the solution.

Make function to check if the number is prime number-> if the num is prime number, it will add to the result. if not, i will not.

However, how the result sum up all the prime numbers?
I cannot find the code for adding up.

Please explain which point I am missing.
Thank you in advance.

SumPrimes is “recursive,” meaning it calls itself repeatedly.In the return statement is where the summing happens - nonprimes simply pass the next iteration, while primes add themselves to a possibly deeply nested math expression.