Theorem 2p1e3

Description: 2 + 1 = 3. (Contributed by Mario Carneiro, 18-Apr-2015)

	Ref	Expression
Assertion	2p1e3	$$⊢2+1=3$$

Proof

Step	Hyp	Ref	Expression
1		df-3	$$⊢3=2+1$$
2	1	eqcomi	$$⊢2+1=3$$