Theorem 4re

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

	Ref	Expression
Assertion	4re	|- 4 e. RR

Proof

Step	Hyp	Ref	Expression
1		df-4	|- 4 = ( 3 + 1 )
2		3re	|- 3 e. RR
3		1re	|- 1 e. RR
4	2 3	readdcli	|- ( 3 + 1 ) e. RR
5	1 4	eqeltri	|- 4 e. RR