Theorem 8p1e9 8050

Description: 8 + 1 = 9. (Contributed by Mario Carneiro, 18-Apr-2015.)

Assertion

Ref	Expression
8p1e9	|- ( 8 + 1 ) = 9

Proof of Theorem 8p1e9

Step	Hyp	Ref	Expression
1		df-9 7980	. 2 |- 9 = ( 8 + 1 )
2	1	eqcomi 2044	1 |- ( 8 + 1 ) = 9

Syntax hints:   = wceq 1243  (class class class)co 5512   1c1 6890   + caddc 6892   8c8 7970   9c9 7971

This theorem was proved from axioms:  ax-1 5  ax-2 6  ax-mp 7  ax-ia1 99  ax-ia2 100  ax-ia3 101  ax-5 1336  ax-gen 1338  ax-ext 2022

This theorem depends on definitions:  df-bi 110  df-cleq 2033  df-9 7980

This theorem is referenced by: (None)