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	$$⊢6+1=7$$