Description: 9 + 7 = 16. (Contributed by Mario Carneiro, 19-Apr-2015)
Ref | Expression | ||
---|---|---|---|
Assertion | 9p7e16 | |- ( 9 + 7 ) = ; 1 6 |
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 |