Theorem addcomnni

Description: Commutative law for addition. (Contributed by metakunt, 25-Apr-2024)

	Ref	Expression
Hypotheses	addcomnni.1	|- A e. NN
	addcomnni.2	|- B e. NN
Assertion	addcomnni	|- ( A + B ) = ( B + A )

Proof

Step	Hyp	Ref	Expression
1		addcomnni.1	|- A e. NN
2		addcomnni.2	|- B e. NN
3	1	nncni	|- A e. CC
4	2	nncni	|- B e. CC
5	3 4	addcomi	|- ( A + B ) = ( B + A )