Theorem 9p5e14

Description: 9 + 5 = 14. (Contributed by Mario Carneiro, 19-Apr-2015)

	Ref	Expression
Assertion	9p5e14	$$⊢9+5=14$$

Proof

Step	Hyp	Ref	Expression
1		9nn0	$$⊢9\in {\mathbb{N}}_0$$
2		4nn0	$$⊢4\in {\mathbb{N}}_0$$
3		3nn0	$$⊢3\in {\mathbb{N}}_0$$
4		df-5	$$⊢5=4+1$$
5		df-4	$$⊢4=3+1$$
6		9p4e13	$$⊢9+4=13$$
7	1 2 3 4 5 6	6p5lem	$$⊢9+5=14$$