Metamath Proof Explorer


Theorem times2d

Description: A number times 2. (Contributed by Mario Carneiro, 27-May-2016)

Ref Expression
Hypothesis 2timesd.1 φA
Assertion times2d φA2=A+A

Proof

Step Hyp Ref Expression
1 2timesd.1 φA
2 times2 AA2=A+A
3 1 2 syl φA2=A+A