Theorem 2m1e1OLD

Description: Obsolete version of 2m1e1 as of 10-Jun-2026. (Contributed by David A. Wheeler, 4-Jan-2017) (Proof modification is discouraged.) (New usage is discouraged.)

	Ref	Expression
Assertion	2m1e1OLD	$$⊢2-1=1$$

Proof

Step	Hyp	Ref	Expression
1		2cn	$$⊢2\in ℂ$$
2		ax-1cn	$$⊢1\in ℂ$$
3		1p1e2	$$⊢1+1=2$$
4	1 2 2 3	subaddrii	$$⊢2-1=1$$