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Math training - how do you do it?

Anonymous A

Hi guys,

I have been using the Math Tool for a while now (easy/medium-random level) and I am really improving! Everything on the easy level is fine (matter of training) but I am looking for some math tricks on the medium-level questions.

So things to solve 1243/17=? or 1334*21, etc.

I struggle with the approach for these multiplications, and am aware there is some tricks for this. Any good websites you guys know of with tricks (metal math) to solve these questions?

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Anonymous A replied on 09/27/2016

Thanks for the replies guys!

I know (and use) caseinterviewmath.com as well. A good website indeed, but only for practicing. They don't provide "tips and tricks" on how to solve sums like the aforementioned. Of course, one way is to use paper, and this might indeed be enough for cases. But if someone does know some "tips and tricks" I would love to hear of them (also, some of these tricks might have to be performed on paper as well).

An example of the tricks I am referring to:

- 227 : 5 = ? Instead of computing it the long way (7*5+20*5+200*5) you can multiple the first number by 10 (to make 2270) and than take half of it (1135, which is the answer). Goes for any division by 5 obviously.

- 19*18 = ? Although this one is easy to do the conventional way, an alternative is the trick of (1) adding the first digit of the lowest number to the highest number (= 8 +19 = 27), then (2) multiply this by 10 (= 27 * 10 = 270) and then (3) adding the product of the first two digits of both numbers (= 9 * 8 = 72), resulting in 270 + 72 = 342. This only works up to a multiplication of the numbers UNDER 20.

Dorjan replied on 10/14/2016

google Vedic Math

Christina replied on 09/30/2016

There are books that teach those kinds of tricks. It's been a while since I've read one, but Rapid Math Tricks is an example book. You might find it at a library.

Anonymous B replied on 09/28/2016

Are there math drills with equations on some website, or like how it is given in a case usually? Story to math.

Andrew replied on 09/27/2016

I think for problems like this it is entirely appropriate to just work it out on paper. You could try to whiz through it with mental math calculations but I simply work the calculations on paper.

Guennael replied on 09/27/2016
Ex-MBB, Experienced Hire; I will teach you not only the how, but also the why of case interviews

Make sure to use caseinterviewmath.com as well, great website (and free)

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