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Percentage Math Practice

calculation mental math
New answer on Nov 16, 2020
3 Answers
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Mark asked on Jul 18, 2018

Hey guys!

I am looking for a math tool to practice calculation of percentages such as margins. The traditional mental math training tools from and preplounge only train to caclulate absolute numbers form percentage rate, but not percentages such as margins from absolute numbers. I am looking for calculations such as 25m/40m etc.

Does anyone know a tool or qa way to practice these calculations?

Best wishes!

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Best answer
replied on Jul 18, 2018
McKinsey Senior EM & BCG Consultant | Interviewer at McK & BCG for 7 years | Coached 350+ candidates secure MBB offers

Hi Mark,

I am not sure I understand your challenge. Performing this kind of calculations will already give you the percentage, just expressed as a decimal figure (0,625 or 62,5% in your above example).

What you can do is to just create a simple excel sheet where you generate two random numbers as numerator and denominator:


Paste this formula into two cells, and then just divide the numerator by the denominator to get the result (you can put this on a different tab to hide it if you want). Then do the calculation manually and check the correctness of your result. To generate new random numbers just place the cursor on an empty cell and hit DEL.

Cheers, Sidi

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Content Creator
replied on Nov 16, 2020
McKinsey | Awarded professor at Master in Management @ IE | MBA at MIT |+180 students coached | Integrated FIT Guide aut


Have you tried the GMAT prep from The Economist? It helped me a lot.

Hope it helps!



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Anonymous replied on Jul 22, 2020
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Sidi gave the best answer


McKinsey Senior EM & BCG Consultant | Interviewer at McK & BCG for 7 years | Coached 350+ candidates secure MBB offers
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