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Metamath Proof Explorer
Description: 8 + 1 = 9. (Contributed by Mario Carneiro, 18-Apr-2015)
|
|
Ref |
Expression |
|
Assertion |
8p1e9 |
⊢ ( 8 + 1 ) = 9 |
Proof
| Step |
Hyp |
Ref |
Expression |
| 1 |
|
df-9 |
⊢ 9 = ( 8 + 1 ) |
| 2 |
1
|
eqcomi |
⊢ ( 8 + 1 ) = 9 |