Theorem 1p5e6

Description: 1 + 5 = 6. (Contributed by SN, 24-Aug-2026)

	Ref	Expression
Assertion	1p5e6	$$⊢1+5=6$$

Proof

Step	Hyp	Ref	Expression
1		df-5	$$⊢5=4+1$$
2	1	oveq2i	$$⊢1+5=1+4+1$$
3		ax-1cn	$$⊢1\in ℂ$$
4		4cn	$$⊢4\in ℂ$$
5	3 4 3	addassi	$$⊢1+4+1=1+4+1$$
6		1p4e5	$$⊢1+4=5$$
7	6	oveq1i	$$⊢1+4+1=5+1$$
8		5p1e6	$$⊢5+1=6$$
9	7 8	eqtri	$$⊢1+4+1=6$$
10	2 5 9	3eqtr2i	$$⊢1+5=6$$