Mental math added value

Hi Simone,

I agree with the previous comment, mental math is not mainly used as a way to compute how strong on math you are, but rather to analyse three main elements:

1. What is your math speed under pressure: what is your reaction when in the middle of a revenue brainstorming they ask you “what is 72% of 72”?
2. How you communicate your thoughts: what is your way to present your analysis/math in few seconds without previous preparation?
3. What is your emotional reaction when put under pressure, as for your body language: do you close yourself and become hostile, or simply smile and provide the right conclusion with confidence?

This is due to the fact that, unlike other jobs requiring math in the engineering and physics fields, in consulting you have a relevant and continuous client interaction. Mental math questions may thus easily arise with a client in the form of a challenge to your reasoning such as “How can you be sure we will be able to save $5M in just six month?”. In these situations you definitely cannot take your phone or calculator and digit in front of the client or you will lose all your credibility. In short, what they want to test is “What happens if my current client meets this guy alone and challenges him as he is doing with me every day?”

As a consequence, in most cases the kind of math required is also pretty simple. That’s because the interviewer already knows you are smart and can do the math (they screened that when reviewing your CV) and he is more interested in analysing the previous elements.

Hope this helps,
Francesco

Completely agree with everything above. Almost every client meeting you have to calculate to calculate something mentally. Moreover, mental maths really helps while checking your team models and deliverables. You can quickly check the numbers and find the mistakes

I see your points! It is much more clear now, thanks!