Theorem 4re

Description: The number 4 is real. (Contributed by NM, 27-May-1999)

	Ref	Expression
Assertion	4re	⊢ 4 ∈ ℝ

Proof

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