Calculator Brain Share definition Flag Somebody who can do complex math equations in their brain in a matter of seconds. Person 1: What is 356x751? Person 2: Uhhhhhhhh Person 3: 267356 Person 1: What a calculator brain. Calculator Brain by skmad1212 June 28, 2013 0 0 Get merch Get the Calculator Brain mug. Buy Now — $32.95 See more merch