Metamath Proof Explorer


Theorem 2timesd

Description: Two times a number. (Contributed by Mario Carneiro, 27-May-2016)

Ref Expression
Hypothesis 2timesd.1 φ A
Assertion 2timesd φ 2 A = A + A

Proof

Step Hyp Ref Expression
1 2timesd.1 φ A
2 2times A 2 A = A + A
3 1 2 syl φ 2 A = A + A