Metamath Proof Explorer


Theorem 7odd

Description: 7 is an odd number. (Contributed by AV, 20-Jul-2020)

Ref Expression
Assertion 7odd 7 ∈ Odd

Proof

Step Hyp Ref Expression
1 df-7 7 = ( 6 + 1 )
2 6even 6 ∈ Even
3 evenp1odd ( 6 ∈ Even → ( 6 + 1 ) ∈ Odd )
4 2 3 ax-mp ( 6 + 1 ) ∈ Odd
5 1 4 eqeltri 7 ∈ Odd