What is the sum of 2 numbers is 20 and the differance is 4

Question

I am in collage and i need to know it cause i totally forgot and if u dont belive me dont answer this qustion.

Answer 1

n + m = 20

n - m = 4

Add the two equations and get

2n = 24

n = 12

Now plug n=12 into either equation and get m. Using the top equation,

12 + m = 20

m = 8