2+2=4

Yes, 2+2=4.

If you want a quick justification (using Peano axioms):

• Let 0 be zero and S(n) the successor (so S(0)=1, S(S(0))=2, etc.).
• Define addition by 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.

Want me to generate some practice problems or go over addition properties (commutativity, associativity) for exam prep?