Domain Deep-Dives · 9 min read
Consulting Interview Deep-Dive: Case Math, Exhibits & Fit Questions
Beyond frameworks — the math speed, chart-reading, and fit answers that actually separate offers.
Once you can structure a case, the offer is decided by three things candidates under-practice: fast, accurate math; clean interpretation of exhibits; and crisp fit answers. Firms assume everyone can recite a framework — they separate candidates on execution and personal impact. This deep-dive covers the parts most guides skip.
Case math without a calculator
- •Round early and adjust later — work with friendly numbers, then correct once at the end.
- •Use scientific shorthand for big numbers: 3.2 billion becomes 3.2 with nine zeros; track zeros separately from digits.
- •Percentages are reversible: 16% of 25 is the same as 25% of 16, which is 4. Flip to the easier one.
- •Growth: for small rates over few years, approximate compounding as simple (7% for 3 years is roughly 22%).
- •Always narrate the calculation so a small slip doesn't cost you the whole answer.
Reading exhibits and charts
Brainteasers and estimation
Some rounds include a quick estimate or logic question. They test composure and structure, not trivia. Restate the question, lay out an approach before calculating, state assumptions clearly, and sanity-check. Being organized under a curveball is the whole point.
Fit / PEI questions
McKinsey's PEI and BCG/Bain fit rounds probe leadership, drive, and impact through your own stories. They go deep — expect layers of 'why' and 'what exactly did you do'. Prepare two or three stories per theme (leadership, personal impact, entrepreneurial drive) in STAR, and be ready to defend the details.
- •Pick stories where YOU drove the outcome, not the team broadly.
- •Know the numbers and specifics cold — they will drill in.
- •Show reflection: what you learned and would do differently signals maturity.
Run a live case
Practice math, exhibits, and structure together in the Case Simulator's multi-turn cases.
Run a live case →