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Chief
The mental math is pretty easy - shouldn’t need one
D2, yeah that I did. More details below btw
Pro
I've literally never had a case interview where you could use a calculator
And also I do think mental math is a part of our job - looking at two numbers and casually estimating a percent or ratio isn't uncommon
Agreed units are simple, more details below.
LoL. Did you not prepare at all?
The point of those questions is to test your numeracy quickly. If you can't do simple calculations without a calculator, you won't be doing them in the team room during a problem solving session to quickly check and discard hypotheses or sense check others' conclusions.
People who pull out a calculator for simple calculations (and none of the calculations in a McKinsey interview are complex) are people who actively avoid thinking about math. They won't be good thought partners in problem solving.
Interesting - could you give an example of what you mean by engineering calculation ?
More details below
I did 50+ interviews for McKinsey and know the rubric well, and have seen 100+ different cases we give. OP I’m sorry you had a bad experience. But to be clear we would never ask for an integral to be done in a case interview. If that was what you ended up doing it’s most likely you over complicating the situation /case
^This. You overcomplicated it. This is actually a problem when you do a case interview in a field you have a lot of knowledge in. Seen many a candidate botch things up because of this.
Whether you choose to believe it or not, you ended up doing something very wrong. There is literally no case study in the library that requires anything remotely more complicated than Algebra. Integrals? You brought undergrad engineering crazy to a case where you needed to multiply and divide.
Please stop. You think you’ve exposed some kind of glitch in the matrix and instead you’re just establishing that you very likely solved the wrong problem.
Give us an example please; not the exact one but something like it would suffice. I’m a McK interviewer and genuinely curious.
More details below
Won’t say exactly what but started on topics similar to battery capacity, cells/packs, gWh, and continued on
D1 - love the insight! But I’m guessing there was a typo in there and you meant 2.4 billion?
Chief
How did you get an interview with McK without knowing that calculators aren’t allowed in a case interview? I’m legitimately curious. Did you do no research at all? That isn’t some tightly guarded secret.
I’m also curious like others to know what “engineering calculations” McK asked you to work through. Are they in the business of building bridges or semiconductor manufacturing now???
Are you serious? Of course I knew calculators weren’t allowed. When it came to the more complex questions at the end is when I made it clear in a real life scenario I would have resources to perform the proper work, one being the calculator I had at my desk and if I could use that. I was told not to use it and just provide an estimate which I did and still got it correct.
OP - I hear ya. But unless you share a clear illustrative example, people are going to give the benefit of the doubt to the McK Interview process and roast you here.
Pro
I am honestly super confused about this OP
I seriously doubt that they actually made you so derivatives and integrals on your head
Pro
Yea regardless of how simple the only way I can see it happening is as you said if the interviewer said he would need to do it to calculate something (even though he didn’t need to) and the interviewer let him go for it just to see how far he would go
Midway through my interview they told me I couldn’t have a team of analysts and consultants there to work through cases.
LOL WUT…I’m just doing what I’d do on the job. Huh…
Pro
I left consulting last year and this struggle has been real. I have to do all the analysis myself and put it in slides and schedule the meetings AND GET MY OWN COFFEE.
Rising Star
Yeah but someone who’s comfortable and quick with mental math is more likely to notice a calculation error on a slide or that their spreadsheet’s a bit off. Also less likely to make a stupid mistake when put on the spot in front of clients.
Chief
Welll, live and learn I guess. Sorry this happened - you may not have blown your shot so don’t worry
And you can't use Excel when taking the CFA. Lots of artificial hurdles in life
Rising Star
I’m never touching a financial calculator again
This is part of the game. I worked on my mental math for months before case interviews. It weeds out those who are really serious and those who aren’t. There are always shortcuts on the math that you start to see as you practice case math
Since everyone clearly is trying to roast or show sarcasm, thank you :)
For more details: some of the more technical math work was on battery architecture and cooling models. Some of these involve integrals and other equations. Never have seen anything like that in all case preps and interviews that I’ve done, even ones that were technical
Chief
I think we’re all making the assumption that your case interview was for the same kind of position as other case interviews.
Were you interviewing for a specific SME position or something similar that requires that in-depth knowledge of the technology?
Idk no calculator is part of the game. You going to do a back of napkin margin calculation in front of a client with a calculator?
I suck at mental math and I don’t hide it (nor do I need to). I make fun of the fact I’m the theoretical physicist in the room and still need to use my phone calc all the time. Clients have a laugh, I relax, good numbers follow.
FYI: The percentage and ratios were the easy ones. I was asked some engineering calculations outside of that
Sarcasm, nice. More details below
Large division and multiplication does not constitute an engineering problem in my opinion