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Metamath Proof Explorer

Theorem 3z

Description: 3 is an integer. (Contributed by David A. Wheeler, 8-Dec-2018)

Ref Expression
Assertion 3z 3 ∈ ℤ

Proof

Step Hyp Ref Expression
1 3nn ⊢ 3 ∈ ℕ
2 1 nnzi ⊢ 3 ∈ ℤ