Verifying equality with Modulos

savecancel

Hello,

I would like to verify an equality such as

((a+b)%n-b)%n == a

with, naturally, integer numbers. But i couldn't find how to declare integer but empty variables in Sage in order to test such an equality, without declaring precise and specific numbers (which would be useless, I want to verify it for any number of Z).

Any idea? Thanks