Theorem 9pos

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

	Ref	Expression
Assertion	9pos	$$⊢0<9$$

Proof

Step	Hyp	Ref	Expression
1		8re	$$⊢8\in ℝ$$
2		1re	$$⊢1\in ℝ$$
3		8pos	$$⊢0<8$$
4		0lt1	$$⊢0<1$$
5	1 2 3 4	addgt0ii	$$⊢0<8+1$$
6		df-9	$$⊢9=8+1$$
7	5 6	breqtrri	$$⊢0<9$$