Description: 7 is an odd number. (Contributed by AV, 20-Jul-2020)
Ref | Expression | ||
---|---|---|---|
Assertion | 7odd | ⊢ 7 ∈ Odd |
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 |