Theorem 4re

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

	Ref	Expression
Assertion	4re	$$⊢4\in ℝ$$

Proof

Step	Hyp	Ref	Expression
1		df-4	$$⊢4=3+1$$
2		3re	$$⊢3\in ℝ$$
3		1re	$$⊢1\in ℝ$$
4	2 3	readdcli	$$⊢3+1\in ℝ$$
5	1 4	eqeltri	$$⊢4\in ℝ$$