Metamath Proof Explorer


Theorem 6p1e7

Description: 6 + 1 = 7. (Contributed by Mario Carneiro, 18-Apr-2015)

Ref Expression
Assertion 6p1e7 6+1=7

Proof

Step Hyp Ref Expression
1 df-7 7=6+1
2 1 eqcomi 6+1=7