Theorem 4m1e3

Description: 4 - 1 = 3. (Contributed by AV, 8-Feb-2021) (Proof shortened by AV, 6-Sep-2021)

	Ref	Expression
Assertion	4m1e3	$$⊢4-1=3$$

Proof

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