Theorem 3p3e6

Description: 3 + 3 = 6. (Contributed by NM, 11-May-2004)

	Ref	Expression
Assertion	3p3e6	$$⊢3+3=6$$

Proof

Step	Hyp	Ref	Expression
1		df-3	$$⊢3=2+1$$
2	1	oveq2i	$$⊢3+3=3+2+1$$
3		3cn	$$⊢3\in ℂ$$
4		2cn	$$⊢2\in ℂ$$
5		ax-1cn	$$⊢1\in ℂ$$
6	3 4 5	addassi	$$⊢3+2+1=3+2+1$$
7	2 6	eqtr4i	$$⊢3+3=3+2+1$$
8		df-6	$$⊢6=5+1$$
9		3p2e5	$$⊢3+2=5$$
10	9	oveq1i	$$⊢3+2+1=5+1$$
11	8 10	eqtr4i	$$⊢6=3+2+1$$
12	7 11	eqtr4i	$$⊢3+3=6$$