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Metamath Proof Explorer

Theorem 9re

Description: The number 9 is real. (Contributed by NM, 27-May-1999)

Ref Expression
Assertion 9re 9 ∈ ℝ

Proof

Step Hyp Ref Expression
1 df-9 ⊢ 9 = ( 8 + 1 )
2 8re ⊢ 8 ∈ ℝ
3 1re ⊢ 1 ∈ ℝ
4 2 3 readdcli ⊢ ( 8 + 1 ) ∈ ℝ
5 1 4 eqeltri ⊢ 9 ∈ ℝ