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[EN VIDÉO] How to reconcile with mathematics? Normalien, agrégation in mathematics and holder of a master’s degree in the history of religions, Hervé Lehning has devoted himself entirely, since 2010, to the popularization of science, in mathematics, computer science and cryptology. In this video, he gives some simple ideas to play down and facilitate access to mathematics.
L’addition of two numbers in the Egyptian system is relatively easy since it suffices to bring together the different symbols of each number to obtain the sum. Thereby :
Eventually, there may be deductions but this hardly poses a problem. problem. The question is much more complicated to multiply!
Question: how did the ancient Egyptians multiply?
Answer: The ancient Egyptians invented a method that only requires multiplying by two, which is like adding. Traces of this formula are found in Abyssinia… and in Russia !
Take the example of the multiplication : 253 x 13. And write the smallest of these numbers as a sum of powers of two: 8 + 4 + 1. The operation becomes: 253 x (8 + 4 + 1). If we calculate the multiples of 253 by 2, 4 and 8, we are led to perform a simple addition. So you just need to know how to multiply by two!
We did not use theegyptian writing numbers to show that the algorithm itself is simplemoreover this way of multiplying is always applicable!
Remark
Those familiar with base two will notice that writing 13 as a power of 2 sum is the same as writing it in base two.
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