Answer:
5
Step-by-step explanation:
Prime number are Numbers that can only be divisible by itself and 1. Example includes 2, 3, 5, 7, 11.. et c
Note that 1 is not a prime number.
Given two values 63 and 21.
The prime number in 63 is 3
The prime number in 21 is 2
The sum of both prime numbers gotten is 2+3 = 5
