- Introduction: Overview and Background
Introduction & Background
Context of Quant Problems in Case Interviews
Math Skills Required for Case Interviews
Course Requirements and Math Review (Optional)
- FastMath: Multiplication & Division
Division & Factoring — Part 1
Division & Factoring — Part 2
Multiplication & Division Practice Problems
Mental Math Regular Exercises
- Detail: Multiplying & Dividing by "Clean" Numbers
Multiplying & Dividing by 25
Multiplying & Dividing by 5 & 50
- FastMath: Percentages & Percentage Growth
Percentages & Compound Growth - Part 1
Percentages & Compound Growth - Part 2
Percentages & Compound Growth - Part 3
- Quant Case Problems
Quant Case Problems Overview
Breakeven Analysis — Problem 1
Breakeven Analysis — Problem 2
Economies of Scale
Market Sizing & Estimation Overview
Market Sizing — Example 1
Market Sizing — Example 2
Market Sizing & Estimation — Recommendations
Growth Rate Analysis
Chart Reading 1
Chart Reading 2: Highly Recommended
- Summary & Conclusion
Summary & Conclusion
- Advanced Quant Topics
NPV 1 — Net Present Value Overview
NPV 2 — Perpetuities & NPV Examples
Calculating Doubling (& Halving) Time with Rule of 72
Compound Growth Calculations
NPV 3: Perpetuities with Growth
NPV 4: NPV Sensitivity to Growth & Discount Rates
- Advanced Quant Case Problems
Production Shifting (McKinsey Case)
Pipeline Analysis: Algebraic Solution
- Case Library
Investment Decision - Full Case
Competitive Pricing Response
FastMath Ace the Case
Ace the Quantitative Component of Case Interviews
Hello! My name is Matthew Tambiah and I’m the creator of the FastMath Ace the Case Online Course. I’m a former McKinsey consultant and I designed this video-based online course specifically to teach you the quantitative and mental calculation skills you need to succeed in Management Consulting Case Interviews.
Many people are intimidated by math and quantitative problems given in Case Interviews as you can’t use calculators in the interview. In this online course, I will teach you the mental-calculation methods I personally used to successfully navigate the McKinsey Case Interview process. I used similar methods throughout my academic career and they helped me gain entry to, and graduate from, both Harvard and MIT.
In the FastMath Ace the Case Online Course, I use on-demand video instruction to teach FastMath calculation methods designed specifically to simplify the type of calculations required in Case Interviews at elite Management Consulting firms like McKinsey, Bain and BCG. These FastMath calculation methods will make you faster and more efficient and reduce your calculation errors by drastically simplifying most Case Interview calculations (Case Calculations). I will also show you how to apply these FastMath calculation methods to the most common types of Case Interview quantitative problems, such as Market Sizing & Estimation problems and Break-even Analysis problems.
The FastMath Ace the Case Online Course is different from other quantitative interview-preparation resources because it uses on-demand video lessons to teach you how to do Case Calculations faster and more efficiently, whereas most other quantitative interview-prep resources simply provide practice problems and answers — without teaching methods to efficiently perform the calculations without a calculator. Furthermore, all the calculation methods in this course are designed for the types of calculations you will actually encounter in a Case Interview, and all the example problems are based on problems given in actual Case Interviews at elite Management Consulting firms, while many other resources use examples that don't effectively simulate actual Case Interview problems.
The FastMath Ace the Case Online Course will enable you to maximize your performance in Case Interviews, and is the recommended quantitative preparation resource for the consulting clubs at Wharton, Columbia Business School, London Business School and numerous other MBA programs. More than 5,000 candidates world-wide have used the FastMath Ace the Case Online Course to prepare for Management Consulting interviews. Discover why top MBA students love FastMath, and maximize your own interview performance by registering for the FastMath Ace the Case Online Course.
You can preview several lessons — see the blue links on the right.
The FastMath Ace the Case Online Course has two components. In the first half of this course I will teach you a set of FastMath calculation methods, which will enable you to do multiplication, division, percentage and compound growth calculations faster and more efficiently without a calculator — as required in Case Interviews. In the second half of this course, I’ll show you how to apply the FastMath calculation methods to the most common types of quantitative problems given in case interviews, such as Market Sizing & Estimation problems, and Break-even Analysis problems. I will illustrate the most efficient solution method for each problem type and show how to use the FastMath calculation methods to solve the problems quickly and efficiently. I will also highlight how to use the quantitative results to develop Case insights and recommendations. I’ll provide you with numerous full Case Interview example quant problems with detailed solution methods, and comprehensive practice problems and solution methods that reinforce the course material.
Mental Math Methods
Quant Problems Types
30-day Money-back Guarantee
If you're unhappy with this course for any reason, email me and I will give you a refund.
Articles on Math Skills in the Context of Case Interviews
Real Case Calculations and Case Numbers
Before I created this course, I looked at numerous quantitative problems that top Management Consulting firms like McKinsey, Bain, BCG, Accenture and Deloitte had given to their candidates in Case Interviews. I then created the course content to teach people the most effective ways to solve the actual problem types elite Management Consulting firms were asking candidates to solve.
By looking at the actual calculations required in Case Interview, I also noticed that the specific numbers involved in the Case Calculations, which I will refer to as Case Numbers, had specific properties you could use to simplify the calculations — if you knew the proper calculation methods. The Case Numbers showed signs of being carefully chosen, and the calculation methods I teach in the FastMath Ace the Case Online Course are designed specifically for the actual calculations required in Case Interviews.
Case Numbers are usually “Round” numbers with a few significant digits, such as 300,000 or 4,000,000. Some people may be intimidated by having to do a calculation like (4,000,000 × 20,000) without a calculator. In this course, I’ll teach you efficient methods to manage the zeroes (see Multiplication Lesson), so that calculations like these will become easy. When Case Numbers have more than one significant digit, they usually have certain characteristics that can make calculations like multiplication and division much easier.
Example Case Calculation
You are told that a company sells a Product for $32 per unit and sells 25,000 units per year, and then you are asked to calculate the Revenue.These numbers are representative of actual Case Numbers, and you would need to do the calculation: ($32 × 25,000). You can execute this calculation by multiplying (32 × 25) and then writing the three zeroes from “25,000” at the end of this result. Here is a way to efficiently perform the calculation (32 × 25) using relevant characteristics of these Case Numbers.
First decompose 25 as: (25 = ¼ × 100). Then perform the calculation using this decomposition of 25.
32 × ¼ = 32 ÷ 4 = 8
8 × 100 = 800
Therefore (32 × 25 = 800). You can (and should) verify this with a calculator or pen and paper. This method works because (25 = ¼ × 100), and so (4 × 25 = 100); so, when you divide 32 by 4, the result is the “number of groups of 100.” In general, to multiply any number N by 25, you divide N by 4, and then multiply the result by 100. Now the answer to our original problem of ($32 × 25,000) is then $800,000.
Most multiplication and division calculations required in actual Case Interviews involve numbers like this for which there is a way to dramatically simplify the calculation. In the Fastmath Ace the Case online course, I’ll provide you with a comprehensive set of methods for multiplying and dividing with the Case Numbers you are most likely to encounter in actual Case Interviews.
Beware of “Imposter” Case Calculations and Case Numbers”
Many other quantitative Case Interview preparation resources have example calculations with Case Numbers you are highly unlikely to encounter in an actual Case Interview, such as multiplying by a number like 23,487 — or a number with five (or more, significant digits. Practicing calculations with numbers with many significant digits is not an effective way to prepare for Case interviews as these calculations are not representative of actual Case Numbers or Case Calculations. You will be practicing brute-force mechanical calculation skills which you won’t need in Case Interviews, and won’t get experience looking for and finding methods to simplify calculations.
If you see example problems where you are multiplying or dividing by numbers with four or more significant digits, or adding numbers with five or more significant digits, this is a red flag indicating these calculations are likely “made up” and not representative of actual Case Numbers and Case Calculations. As a result, there are no longer efficient methods to perform the calculation — and practicing with these types of problems is not an effective way to prepare for actual Case Interviews.
All the calculation methods, example problems, and practice problems in the Fastmath Ace the Case Online Course are based on actual Case Calculations (and the specific Case Numbers involved) from leading management consulting firms like McKinsey, Bain, BCG, Accenture and Deloitte. Therefore, I believe the FastMath Ace the Case Online Course is the best quantitive Case Interview preparation resource because the material is based on what you will encounter in actual Case Interviews.
Quant Self-diagnostic Quiz
Mental Math Exercises
Former McKinsey Consultant
- Bachelor's from Harvard with Highest Honors in Electrical and Computer Engineering
- MBA from MIT Sloan
My name is Matthew Tambiah and I am the creator of the FastMath Ace the Case Online Course. I have taught FastMath Ace the Case Workshops at Harvard Business School, Wharton, MIT, London Business School, INSEAD, Georgetown and numerous other leading universities. Thousands of candidates from around the world have used the FastMath Ace the Case Online Course to prepare for Case Interviews. My students have joined McKinsey, Bain, BCG, PwC, Accenture, Deloitte, Booze Allen, and other leading consulting firms. I have a Bachelor's degree from Harvard with Highest Honors in Electrical and Computer Engineering. Before I attended the MBA program at MIT, I worked at Akamai Technologies, a leading computer networking firm, in both Silicon Valley and Cambridge, Massachusetts, in sales engineering, product management and product marketing roles.
Math and science subjects always came naturally to me and I frequently helped friends with these subjects in high school, in college at Harvard, and in graduate school at MIT. I have received the following scores on math and science standardized tests
- Math SAT: 800/800
- GMAT: 99th
- Advanced Placement BC Calculus: 5/5
- Advanced Placement Physics C Mechanics: 5/5
- SAT Mathematics Level 2 Subject Test: 800/800 (formerly named the SAT Math II Achievement test)
I developed the concept for the FastMath Ace the Case Online Course when I was in business school at MIT. I was enrolled in the 2-year MBA program at MIT, and I spent the summer between the first and second year working in the technology practice at McKinsey. When I returned to school in the fall of my second year, many classmates asked me to help them prepare for their Case Interviews because I had successfully navigated the process. I started giving people some of the Case Interview questions I received, and noticed that many people struggled with the quant problems — even people with strong math and science backgrounds. There were many Case Interview preparation resources, but I didn't think they did a good job helping people prepare for the quantitative component of Case Interviews, so I volunteered to host a workshop on quant skills for Case Interviews for MIT students through MIT Sloan Management Consulting Club. My classmates like the material and this was the inspiration for the current version of the FastMath Ace the Case Online Course.