How good are you at mental arithmetic? Not one of your key strengths? But a skill you consider not that important anyway because we have pocket calculators that are much faster than we are? This might apply to most people out there, but definitely not to all.
This week we came across a most astounding TED Talk in which “Mathemagician” Arthur Benjamin does incredible mental arithmetic: he squares four digit numbers faster than people do when they use a pocket calculator and he knows what weekday a random date was. He even explains how he does the multiplying: First he breaks down the numbers into smaller numbers and multiplies them. He uses a phonetic code to convert numbers into words in order to store them as words and then convert them back into numbers at a later stage. Sounds easy, but most likely only to him.