Theorem 8lt9

Description: 8 is less than 9. (Contributed by Mario Carneiro, 19-Feb-2014)

	Ref	Expression
Assertion	8lt9	$$⊢8<9$$

Proof

Step	Hyp	Ref	Expression
1		8re	$$⊢8\in ℝ$$
2	1	ltp1i	$$⊢8<8+1$$
3		df-9	$$⊢9=8+1$$
4	2 3	breqtrri	$$⊢8<9$$