Mental Math Made Easy

Relying on your brain to do some things which machines can do is a great way of improving your brain’s retentiveness and also boost your self-esteem. In choosing to write this article, I have decided to share some age long methods of mental mathematics that I have been using since I was a young child and still use when I’m on the hot seat during examinations or in a meeting or when I want to look cool as sh*t.

  • The first type of mental math I would like to demonstrate is mental addition. Ever had to add big sums without a calculator or a pen and paper only to make a silly mistake? The best of us make mistakes but that doesn’t mean we can’t try our best to reduce the said number of mistakes. Without too much story;
  • Add 323 and 519
  • First of all add 300 and 500.
  • 300 + 500 = 800
  • Then add 23 and 19 (this is where it gets a bit tricky)
  • Take ‘1’ from 23 and add it to 19.
  • This gives 22 + 20 = 42 (which is easier to add than 23 + 19) even though they give the same results.
  • Now add 42 + 800 = 842
  • This is much easier than doing “nine plus three equals twelve; write two, carry one, two plus one is three….”
  • Let us try the same thing for 199 and 744
  • 100 + 700 = 800
  • 90 + 40 = 130
  • 9 + 4 = 13
  • 800 + 130 + 13 = 943
  • Easy right?
  • Try a bit yourself 214 + 441; 6743 + 188;

 

  • The next type is mental multiplication. This follows basically the same pattern as mental addition but let me illustrate with one example.
  • 20 x 17
  • First of all, multiply 20 and 10
  • 20 x 10 = 200
  • Then multiply 20 and 7
  • 20 x 7 = 140 (2 x 7 equals 14; just add a zero at the back)
  • 200 + 140 = 340
  • 20 x 17 = 340.
  • Try 14 x 12; 22 x 8

This is a very good way to massage the ol’ gray matter and also to look cool as shit.


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