Theorem 3m1e2

Description: 3 - 1 = 2. (Contributed by FL, 17-Oct-2010) (Revised by NM, 10-Dec-2017) (Proof shortened by AV, 6-Sep-2021)

	Ref	Expression
Assertion	3m1e2	$$⊢3-1=2$$

Proof

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