Theorem 2lt9

Description: 2 is less than 9. (Contributed by Mario Carneiro, 9-Mar-2015)

	Ref	Expression
Assertion	2lt9	⊢ 2 < 9

Proof

Step	Hyp	Ref	Expression
1		2lt3	⊢ 2 < 3
2		3lt9	⊢ 3 < 9
3		2re	⊢ 2 ∈ ℝ
4		3re	⊢ 3 ∈ ℝ
5		9re	⊢ 9 ∈ ℝ
6	3 4 5	lttri	⊢ ( ( 2 < 3 ∧ 3 < 9 ) → 2 < 9 )
7	1 2 6	mp2an	⊢ 2 < 9