In May 2014, Presh Talwalkar made a YouTube video about how to multiply numbers by drawing lines. By the end of the month, the video received over a million vie

First published in 1202, Fibonacci’s Liber Abaci was one of the most important books on mathematics in the Middle Ages, introducing Arabic numerals and method

Do high-speed, complicated arithmetic in your head using the Trachtenberg Speed System. Ever find yourself struggling to check a bill or a payslip? With The Tra