Cool article and I love the writing style with subtle historic comments like the last sentence here:<p>&quot;&quot;&quot;I was good at mental arithmetic and saved myself a lot of money back in the Soviet Union. Every time I shopped I calculated all the charges as I stood at the cash register. I knew exactly how much to pay, which saved me from cheating cashiers. To simplify my practice, the shelves were empty, so I was never buying too many items.&quot;&quot;&quot;