mental arithmetic

Do not know when to appear, but people have created a lot of recipes, tips to show the usefulness until today (and maybe forever after).

This will be the mental math method

These fast and standard calculation tips will help you a lot when you don't have a computer!

Learn fast calculation methods, mathematical rules that you can't find in textbooks or in school chairs ...

Shakuntala Devi, Indian math genius, was named

Once included in the Guinness Book of World Records for his superhuman mental ability, but a mathematical prodigy in India only works on her own.