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Metamath Proof Explorer

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