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Mental Math ressources

Someone asked on Nov 16, 2018 - 3 answers

Hello,

Do you have any reliable (free online or book) resources to develop mental math techniques? I need a methodology and a way to progress.

Thanks in advance !

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Vlad updated his answer on Nov 16, 2018
McKinsey / Accenture / Got all BIG3 offers / More than 300 real MBB cases / Harvard Business School

Hi,

Basically, you need to develop 3 calculation skills:

1) Learn how to multiply double digit numbers (https://www.youtube.com/watch?v=6ndkkPZYJHo).

2) Learn how to work with zeros. Best way - always use 10^power instead of zeros

Example:

300x9000 = 3*10ˆ2 x 9*10ˆ3=3x9*10ˆ(2+3)=27*10ˆ5

Handwritten it looks not that complicated. If you get used to writing all the numbers that way, you will never loose zeros and all multiplications/divisions will be replaced with + or -.

3) Learn the division table up to 1/11 (i.e. 5/6 = 83.3%). It will help you calculate any percentage problems

Use math tools to train (Preplounge tool, Mimir math for iOS, Math tool on Viktor Cheng website). Train, train, and train again

Good luck!

(edited)

Anonymous B replied on Nov 16, 2018
Guennael replied on Nov 16, 2018
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