Theorem 9p7e16

Description: 9 + 7 = 16. (Contributed by Mario Carneiro, 19-Apr-2015)

	Ref	Expression
Assertion	9p7e16	|- ( 9 + 7 ) = ; 1 6

Proof

Step	Hyp	Ref	Expression
1		9nn0	|- 9 e. NN0
2		6nn0	|- 6 e. NN0
3		5nn0	|- 5 e. NN0
4		df-7	|- 7 = ( 6 + 1 )
5		df-6	|- 6 = ( 5 + 1 )
6		9p6e15	|- ( 9 + 6 ) = ; 1 5
7	1 2 3 4 5 6	6p5lem	|- ( 9 + 7 ) = ; 1 6