Description: 8 + 4 = 12. (Contributed by Mario Carneiro, 19-Apr-2015)
Ref | Expression | ||
---|---|---|---|
Assertion | 8p4e12 | |- ( 8 + 4 ) = ; 1 2 |
Step | Hyp | Ref | Expression |
---|---|---|---|
1 | 8nn0 | |- 8 e. NN0 |
|
2 | 3nn0 | |- 3 e. NN0 |
|
3 | 1nn0 | |- 1 e. NN0 |
|
4 | df-4 | |- 4 = ( 3 + 1 ) |
|
5 | df-2 | |- 2 = ( 1 + 1 ) |
|
6 | 8p3e11 | |- ( 8 + 3 ) = ; 1 1 |
|
7 | 1 2 3 4 5 6 | 6p5lem | |- ( 8 + 4 ) = ; 1 2 |