It is a silly question - but, What's the role of mental math & brain teasers in interviews?

On a related note:

I have always had very positive feedback from interviewers when I told them that I already knew the answer to a given brainteaser, instead of pretending to solve it right then and there.

Bonus points for honesty and backbone, I guess. :-)

Hi Anonymous,

good question, I have asked myself this quite often.

I think we have to view the two things separately:

Mental Math

Yes, we do have calculators on our phone. So for a precise answer, we can always refer to the powerful computing machines around us. Mental math mostly helps to get a feeling for "Wait a second, that doesn't add up" - so to identify at which point it's time to turn on the number cruncher. It's also helpful to be able to do a bit of mental math in moments when you can't easily get out your phone and do the math - while you're presenting something, or in a no-phones meeting.

But I would really be interested in seeing scientific evidence that good mental math performance is a good predictor of job performance.

Brain teasers

Brain teasers, in general, are more a test for creativity and outside of the box thinking. Of course, there are different flavours, some more math-y, some more creative. I guess they test with how many approaches to a solution you can come up with, whether you can look beyond the obvious, whether you can think on your feet, whether you can "feel" your way to a solution. This may help you during your work because if the solution to a problem were obvious, you wouldn't call the highly paid consultants, would you now?

But again, I haven't seen any scientific evidence that brain teaser chops translate into good consulting skills.

Cheers

Elias

Hi,

There is no dedicated part of the interview for brainteasers and to be honest they are quite rare. Although the interviewer might want to ask you a brainteaser question either before or after the case. To prepare you simply read the 2-3 most popular books with the brainteasers (Are you smart enough to work at Google?, How would you move Mount Fuji?).

Best

Hey,
in general I believe it is not mainly about the ability to do mental math.
It is about the competences you show while doing these estimation tasks.

For example the ability to:

• Think fast
• Structure yourself in an understandable way
• Make sound assumptions to solve your problems

Of course it is also about precision - imagine how MC Kinsey would look like in front of their customers if one of their consultants is making several math mistakes in a conversation. It all falls back to the company.

I hope it makes sense.

All the best,
Tobi

Hello!

Teasers are indeed quite weird, but do practice market sizing questions (there are tons solved in the Q&A).

Hope it helps!

Cheers,

Clara