Calculate even faster

Throughout history, calculating better and faster has been an imperative, at the root of important stakes. Methods have multiplied, sometimes in surprising ways. Thus, Descartes used geometry to perform arithmetic operations! Mental calculation, with its tricks, has taken an important place in the teaching of mathematics, even if its approach has been revolutionized by the arrival of computers and calculators. The latter continue to adapt to integrate technological advances and remain essential pedagogical tools. Knowing how to calculate well remains indeed an imperative for good integration into society.

Since the time of Archimedes already, science has been used to detect fraud. Today, the administration uses mathematics, via sophisticated algorithms, to unmask those who hide profits or income. As for the « fallacious proofs », are they swindles? They are closer to magic tricks where the unnoticed error constitutes the « trick » that the game consists of spotting, and are an excellent pedagogical tool to highlight the implicit properties used in certain reasonings.