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Metamath Proof Explorer

Theorem 8lt9

Description: 8 is less than 9. (Contributed by Mario Carneiro, 19-Feb-2014)

Ref Expression
Assertion 8lt9 
|- 8 < 9

Proof

Step Hyp Ref Expression
1 8re 
 |-  8 e. RR
2 1 ltp1i 
 |-  8 < ( 8 + 1 )
3 df-9 
 |-  9 = ( 8 + 1 )
4 2 3 breqtrri 
 |-  8 < 9