Quick and accurate mental arithmetic tips make you surprised

The numbers all have a specific rule, if we know and remember those rules, the calculation will become "as easy as hand". Historically it has recorded many "holy" mental arithmetic that make the whole world respect.

Alexis Lemaire , "the robot" is known for the world's No. 1 quick mental arithmetic. In 2007, at the Museum of Scientific History in London, England, he calculated the 13th root of a 200-digit number in a record time of 70.2 seconds. To this day, the "divine" calculation of the French man is still a milestone for many people to reach.

In order to achieve that "horrific" achievement, in addition to the "giant" brain with superhuman memory, Alexis Lemaire's quick calculation also plays an extremely important role.

So the quick mental arithmetic of the guy born in 1980 has nothing special, but even the mathematical genius is interesting and admirable. Learn and learn the 9 strange calculation tips below, maybe you will break Alexis Lemaire's record.

With multiplication table of 9

"Triangle" calculation of number 1

"Triangle" calculation of number 8

How to quickly calculate 2 multiplication 2-digit numbers

Methods of mental arithmetic with numbers 11

How to practice it!

Multiplication of number 97

Method of adding two fast fractions

See also: 10 methods of teaching children of Jews, every parent should learn