2+2=4

Yes, 2 + 2 = 4.

A quick way to see it (using basic definitions):

• Let 0 be zero, 1 = successor of 0, 2 = successor of 1, etc.
• Addition is defined so that a + 0 = a and a + S(b) = S(a + b).
• Then 2 + 2 = S(S(0)) + S(S(0)) = S(S(S(S(0)))) = 4.

If you’d like, I can give you a few practice problems, or show how this works in different bases or with modular arithmetic.