Crack The Math: consulting math practice book
Mental math speed is trained, not improvised
60 mental math training sessions with 4,000+ exercises and benchmark times. Build the speed and accuracy you need for consulting interviews.
Amazon: paperback
Digital: 6 books, 24 months access
Who is this book for?
Candidates who are slow with mental math during cases and need to build speed to solve calculations in real time without losing the thread of the analysis.
Those who make calculation errors under pressure — who need to train accuracy so that math doesn't become their weakest point during the interview.
Anyone who wants to eliminate math as a weak point in their consulting interviews and turn calculations into a competitive advantage.
Candidates preparing for math-heavy assessment tests like the Bain SOVA, McKinsey Solve numerics, or other quantitative screening tests used in consulting hiring.
What's inside?
60 structured daily training sessions
A complete 2-month program: 1 session per day with progressive difficulty. From basic operations to complex multi-step calculations that mirror real interview scenarios.
56 mental math problems per session
Quick-fire exercises covering percentages, growth rates, ratios, division shortcuts, compound interest and operations with large numbers. Designed to be solved without paper.
8 paper-based business problems per session
Market sizing, break-even analysis, unit economics and other multi-step calculations that require structuring the problem before solving — exactly like in a case interview.
Benchmark times to track your progress
Each session includes time benchmarks so you can compare your speed against the expected standard and verify your improvement week over week.
Progressive difficulty from basic to complex
Early sessions consolidate fundamental operations. Later sessions combine multiple concepts into complex business calculations under time pressure.
How this book works
Consulting interviews and screening tests challenge your quantitative skills under pressure. It's not just about doing math — it's about doing it fast, accurately, and without hesitation while maintaining the thread of the case conversation.
This book is designed as a daily training program, with the intensity of a workout applied to numbers. With 60+ progressive sessions and over 4,000 exercises, you train speed and precision systematically.
Each session combines 56 quick mental math drills (arithmetic and basic algebra) with 8 more complex paper-based problems. Reference times let you measure your progress. Difficulty increases every 10 sessions so you never stop improving.
This book is for you if:
- ●You're preparing for consulting interviews at McKinsey, Bain, BCG or other top firms.
- ●You need to strengthen your mental math for screening tests like the GMAT Focus.
- ●You're looking for a structured daily practice plan that trains both speed and accuracy.
- ●You want an intensive volume of exercises (4,000+) combining mental math and paper-based problems.
About the author
Javier Rotllant — Ex-Associate Partner at Bain & Company. 13 years in strategy consulting, 9 at Bain. Has interviewed over 300 candidates in real MBB hiring processes. This book was born from seeing brilliant candidates fail due to avoidable calculation errors — and from the certainty that math speed is a trainable skill.
Complete your preparation
Get your copy
60 sessions, 4,000+ exercises and benchmark times to master mental math for consulting.
Or access all our books in digital format on the Prep Platform — 450+ pages of exercises, frameworks and real case solutions from a former Bain interviewer.