Theorem 7p4e11

Description: 7 + 4 = 11. (Contributed by Mario Carneiro, 19-Apr-2015) (Revised by AV, 6-Sep-2021)

	Ref	Expression
Assertion	7p4e11	$$⊢7+4=11$$

Proof

Step	Hyp	Ref	Expression
1		7nn0	$$⊢7\in {\mathbb{N}}_0$$
2		3nn0	$$⊢3\in {\mathbb{N}}_0$$
3		0nn0	$$⊢0\in {\mathbb{N}}_0$$
4		df-4	$$⊢4=3+1$$
5		1e0p1	$$⊢1=0+1$$
6		7p3e10	$$⊢7+3=10$$
7	1 2 3 4 5 6	6p5lem	$$⊢7+4=11$$