Techniques for division?

Question

I find my case math division skills are generally ok. I have learned the division table up to 1/11 and find it very helpful for divisions with a single digit diviser.

My main issue is when I am dealing with a multi digit diviser (e.g. 25k / 42 or 825 / 76) because I usually take quite a long time to do the calulation and it is not often accurately done.

What techniques do others use for these sorts of problems?

Thank you very much.

Answer 1

Hi,

I recommend learning a division table. Learn all the numbers until 1/10 (e.g. 1/3 = 33.3%, 1/4 = 25%, 3/4 = 75%, 1/6 = 16.7%, etc)

This method will help you calculate any percentage problems like market shares or margins. For example, if your market is $620M and your revenues are $5.1M you can use 5/6 or 83.3%, as a proxy to calculate the market share. By adjusting to zeroes and slightly decreasing the number, you'll get 8.2%

Best

Answer 2

Hi there,

I agree with David, most interviewers would be fine if you just round the denominator to make the calculation slightly easier (it is all about being 80/20) - if the interviewer insists against the rounding, then it's normal to ask to solve it by hand.

Best of luck in the process.

Khaled

Answer 3

Hello,

Maybe other people will have better ideas than me on this, but I fear that certain divisions must really be put on paper. But I still advise you to propose rounding to your interviewer before embarking on complicated calculations (e.g. divide 25k / 40 vs. 25k / 42).

Best,

David

Answer 4

Hello!

Whenever you find those odd divisions in an MBB/consulting interview, be careful. It´s precisely a trap to see if you can simplify.

For instance, to your examples:

25,000 / 42:
- Round up 42 to 40
- 40 is 4/10, or 2/5
- Now it´s much easier:
  - Divide 25,000/5
  - Then multiply per two

Hope it helps!

Cheers,

Clara

Answer 5

Hi, in addition to all the advices of other coaches I recommend this YT channel - very useful for divisions and math tricks in general:
https://www.youtube.com/playlist?list=PLjbxBzUM6SLnSYop8JXLu9zciW-rn7yyD

Hope it helps,
Antonello

Ps. Preplounge math tool then is great to practice it: https://www.preplounge.com/en/mental-math.php

Answer 6

Dear A,

You can make your calculations easier with round the last number or for division process itself you can put asid all the nulls (but then don't forget to put them back).

Like 25k/42

25 000/40

25/40--> 24/4---> 6

600 appr

Whould it be ok?

Good luck,

André

Answer 7

Hi there,

I highly recommend the following resources:

Online "Drills": https://www.jetpunk.com/quizzes/fast-math-multiplication-quiz
Math sheets (print these and do them on paper): https://www.math-drills.com/
Rocketblocks: https://www.rocketblocks.me/