Theorem 9re

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

	Ref	Expression
Assertion	9re	|- 9 e. RR

Proof

Step	Hyp	Ref	Expression
1		df-9	|- 9 = ( 8 + 1 )
2		8re	|- 8 e. RR
3		1re	|- 1 e. RR
4	2 3	readdcli	|- ( 8 + 1 ) e. RR
5	1 4	eqeltri	|- 9 e. RR