In order to perform math calculations faster, here are some tips you can use:
Best of luck.
Let me share a secret: There's no real benefit in the context of case studies in doing maths relatively fast. In fact, people worrying they're being too slow tend to make stupid mistakes by skipping steps.
"Being slow" at maths in cases generally means the person loses their way, or is trying to solve the wrong problem. Obviously it's a plus if you're a human Excel, but for most people the perfect case interview is simply clearly written down and talked through maths, starting with the problem in words, followed by numbers.
I always advise people to take their time, work through complicated numbers in detail on a separate sheet of paper if necessary and for 95% of people there will be no problem with speed.
I used a very interesting book:
https://www.amazon.com/Secrets-Mental-Math-Mathemagicians-Calculation/dp/0307338401
There are a couple of good apps on the Apple App Store that you can use for practice.
Search "Case Math" and you'll find a few.
Hi Khaoula,
I'm a former McKinsey consultant, and I have a number of methods and recommendtions for doing caculations more efficiently, which leads to much faster calcuations and fewer mistakes.
I disagree with some other responses which say that doing math quickly isn't a benefit in an interview. I have had numeous peoeple who said htey used my methods to solve the quant problmes in Case Interviews quickly, and that the interviewer was defintely impressed. While it's true, that if you try to rush the math, you might make a mistake, you can learn specific methods that are simpler, faster and less error prone.
For example, what is 120 Million times 250? This could come up if they tell you a company sells 120 Million units per year, at $250 per unit. A typical approach would be to use Long-hand multiplication, or to caculate 12 × 25 and count zeroes. These both tend to be somewhat slow, and error prone, especially with counting zeroes.
Here's an efficient methods:
There are a number of other methods like this, and I wrote some articles in the Bootcamp section on quant skills required in Case Interviews.
I have also created the FastMath Ace the Case online course specifically to teach the quant skills needed to succeed in Case Interviews — you can access the course here: http://www.fastmath.net/ace-the-case/?pc=preplounge_bc_001
Enjoy,
Matthew
FastMath Crack the Case: Online Course to Improve Quant Skills
I have created an online, on-demand, video based course, called FastMath Crack the Case, which teaches calculation techniques that are specifically designed to maximize your performance in the quantitative portion of consulting interviews. Discover simple, fast, and efficient calculation techniques which will deliver results in your job interviews. I'm a former McKinsey consultant and a graduate of both Harvard and MIT, and I used these calculation techniques to ace my case interviews, and throughout my educational career.
You can learn more about, and register for the FastMath online course through the URL below. The first 20 people to register will receive a free subscription to the FastMath online course and subsequent registrations will receive a 20% discount to $39.
Registration URL: http://fastmath.skilljar.com/fastmath-crack-the-case?pc=preploungeboard
FastMath Online Course Features
The FastMath Crack the Case online course is the recommended quant training for consulting clubs at Wharton, Columbia Business School, LBS and numerous other MBA programs. Over 5,000 MBA students around the world have used the FastMath online course to prepare for consulting interviews. Learn for yourself why top MBA students love FastMath, and maximize your own interview performance by registering for the FastMath online course.
The FastMath Crack the Case online course is different from other quantitative interview-preparation resources because it uses on-demand video instruction to teach fast and efficient calculation techniques, whereas other quant interview-prep resources usually just provide practice problems and answers, without teaching practical methods for performing the calculations.
The FastMath Crack the Case online course teaches efficient solution methods for the most common types of quantitative case interview problems, such as market sizing problems, and break-even analysis problems, and includes practice problems and solutions which reinforce the course material. There is also a free Quant Self-Diagnostic Quiz available on the course web page.
About Me
I'm is a former McKinsey consultant and has a Bachelor’s with Highest Honors in Electrical and Computer Engineering from Harvard, and an MBA from the MIT Sloan School of Management. My students have joined McKinsey, Bain, BCG, PwC, Accenture, and other leading consulting firms. I'm is also the Quant Coach for MBACASE, the company which markets David Ohrvall’s book, Crack the Case.
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Thanks for this useful tips :) Good luck with your interviews!
That's a really nice overview! Thanks!