Question

This is the problem on my grandson's homework

Answer 1

Choose letters to  represent the unknowns:  x and y.  We are told that x-y = 361.

We could choose any number for x and then calculate y:

Suppose we let x = 500.  Then 500 - y = 361, and y = 139.

Suppose we let x = 1.  Then 1 - y = 361, and y = -360.

And so on.