Struggle Structuring Case Math

Question

Hello everyone,

I’m currently preparing for consulting interviews at BCG and Bain, and I’m struggling with how to structure the math in quantitative case interview questions.

Specifically, I often find it difficult to:

Identify the right scheme, formulas, or relationships to use
Build a clear, logical structure before calculating
Decide on reasonable assumptions and approximations when little information is given

While many resources emphasize that structuring the math before doing calculations is critical, I haven’t found much concrete guidance on how to actually do this in practice.

Beyond the high-level frameworks used for different case types (e.g., profitability, market sizing), are there any generic or repeatable frameworks for structuring math problems in case interviews? In other words, how do you consistently break down an unfamiliar quantitative problem into a clear mathematical structure that feels intuitive and interview-ready?

Any advice, examples, or heuristics would be greatly appreciated. Thanks in advance!

Answer 1

There are techniques for structuring your approach to calculation questions. Feel free to reach out and I can share a guide on this.

High-level:

1 Validate the question and the data

2 Take time then come up with the logic to solve the problem and share it with the interviewer. Once the interviewer validates it...

3 Take time to do the computations, sanity check them, then share them with the interviewer. Once the interviewer confirms the correct result...

4 Interpret the result within the context of the client's mission

However, it sounds like you are particularly struggling with step number 2, as in, coming up with the logic for the calculation.

Reach out if you want a diagnostic on this. We could run through several examples and figure out what is holding you back.

Without being able to diagnose it, the only thing that I can encourage you to do is to practice more, and gradually, with time, you'll get better.

Best,
Cristian