Math Nerves During Interview

case math
New answer on Mar 06, 2021
4 Answers
Anonymous A asked on Mar 04, 2021

I've noticed that I often get serious math nerves during case interview situations. The qualitative part comes easy for me, but I always mess up on the quantitative part. It's usually silly mistakes like 90% = .09, or 1*2 = 3... sigh... Does anyone else experience this? How have you dealth with this in the past?...

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Content Creator
replied on Mar 04, 2021
MBB | 100% personal interview success rate (8/8) and 95% candidate success rate | Personalized interview prep

You need to practice!

Regarding Improving Fast Math Skills

Regarding Improving Axienty

1) Practice, practice, practice - just like playing an instrument, practice until it becomes second nature...then when you perform in front of an audience, muscle memory takes over from stage fright!

2) Practice with people who make you nervous - Don't keep casing yourself or casing with other PrepLoungers! You need to feel as nervous when practicing as you will in the real thing. To do so, you can do any (or all) of the following:

  • Ask for a buddy/case partner from target firms to which you're applying
  • Ask anyone you have a relationship with at your target firms to give you a practice case
  • Ask your school's career office to give you a case
  • Ask a coach to give you a case (and ask them to be tough/strict/non-friendly)
  • Still ask PrepLoungers to case you, but ask them to jump straight into it without conversation beforehand (i.e. simulate the real thing)
  • Change your enviroment - instead of casing at home, go to a library or office room. Changing the scenery may trigger you to be less relaxed

3) Practice with the unknown - ask people to give you "weird" cases. Ask people to throw everything they have at you (curveballs, confusing statements, etc.)'ll get comfortable with tripping up (and recovering)

4) Practice fast math - You said you get nervous here...well, practice it until it's the easiest thing you've ever done! How? Use the following:

Mental Math Q&A:

Interview Anxiety:

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Anonymous A on Mar 04, 2021

Thank you, Ian! :)

Content Creator
updated an answer on Mar 04, 2021
#1 rated McKinsey Coach | Top MBB Coach | 5 years @ McKinsey | Author of the 1% | 120+ McK offers in 18 months

Hey there,

Ken had some excellent points in his answer. The calculation is just one part of a math question in the McKinsey interview.

Before that, you need to:

  1. Discuss the objective and numbers with the interviewer
  2. Layout an approach on how you want to calculate and discuss with the interviewer

After the feared calculations you need to

  1. Communicate your answer top-down
  2. Discuss implications for the client in the context of the case

In addition, throughout all of this, the interviewer will take note of your structure, communication, the creativity of approach, maturity, etc.

There is so much more to math in cases than calculating a few large numbers. Focusing on this extensively is almost always a self-fulfilling prophecy for candidates who throw in the towel as soon as the interviewer hands out some numbers...

That being said, there is no excuse for not performing math drills for hours every day if that is a key weakness for you. Build that math muscle vigorously.

All the best (from someone who also f*cked up math during their actual McK interviews and still got in...)



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Content Creator
replied on Mar 06, 2021
McKinsey | Awarded professor at Master in Management @ IE | MBA at MIT |+180 students coached | Integrated FIT Guide aut


I totally hear you, and this happens to many people -furthermore, it´s easy to see it as an interviewer-.

Interview math, unfortunately, only gets better with practicing. Good news is that there are many ways of doing so!

I would recommend you, for instance, practicing iwth GMAT. There are free exams in the internet that you can use for practice (the one of LBS MBA page, Verits prep, as well as some free trials for courses such as the one of The Economist (

Hope it helps!



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updated an answer on Mar 04, 2021
Ex-McKinsey final round interviewer | Executive Coach

Comfort with numbers comes from familiarity and confidence which is best gained through practice I'm afraid. Through focused practice, you will also find practical tricks that help you avoid silly mistakes too.

The other thing is a change in mindset where math is often more of a hygiene factor than an important differentiator when interviewers are deciding on whether to extend an offer or not. For McKinsey, the "math" section is not just about the arithmetics but how you structure a quantitative problem, how you define and clarify on the key pieces of information, how you find shortcuts to solve a numericla problem, how you pull out insights from exhibits, how you draw out key implications from the "answer" you have calculated, etc. etc.

Good luck!


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Ian gave the best answer


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MBB | 100% personal interview success rate (8/8) and 95% candidate success rate | Personalized interview prep
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