FASTMATH for Business Schools

and Universities

FASTMATH Introduction

Hello! My name is Matthew Tambiah and I’m the creator of FastMath, which teaches mental math and calculation skills for business job interviews through Online Courses, Workshops, and WorkBooks.

FastMath focuses on teaching efficient calculation and problem-solving methods for the quantitative components of business interviews — from simple calculations like calculating Revenue, Profit Margins, and Breakeven volumes to more complex calculations like Market Sizing and Estimation, Investment Analysis decisions, and compound growth calculations. FastMath can help with any interview question that requires a numerical calculation or comparison when formulating an answer.


Matthew Tambiah

  • Former McKinsey Consultant
  • Bachelors from Harvard with highest honors in Electrical     and Computer Engineering
  • MBA from MIT

Trusted by Students From

Calculation Skills Are Essential in Business

Across industries, leading firms such as McKinsey, Bain, Goldman Sachs, Google, Amazon, Facebook, and Netflix require candidates to perform numerical calculations and financial analysis in job interviews without using calculators or spreadsheets. While this might seem unusual, quantitative and calculation skills are critical for diagnosing and solving business problems — so leading firms assess these skills in interviews.

Strong mental calculation skills enable leaders and managers to make faster and better business decisions by allowing them to quickly analyze, interpret and take action, based on quantitative and financial data, and to quickly “run the numbers” and eliminate options that clearly won’t yield results. Mental calculation skills are critical to determining which questions to ask, identifying errors and
aberrations in spreadsheets and computer-generated reports, and pinpointing areas for deeper analysis. Therefore, mental calculation skills are highly valued by many employers — companies that say they seek employees with “strong quantitative skills” usually mean
“strong mental calculation skills.”

A Senior McKinsey partner even wrote a blog post on this topic titled:

Want to get better at business? Practice your mental math.

Calculation Skills Are Essential in Job Interviews in Many Industries

Calculation skills in job interviews aren’t just important for Finance and Consulting Interviews. Field reports from candidates show that companies like Walmart and Amazon routinely require calculations in interviews for leadership positions. For example, Amazon asked leadership development candidates to quantify the financial impact of selling items at the wrong price for a variety of combinations of Prices and Quantities. Walmart asked Marketing candidates to analyze whether Walmart should sell yoga pants — without a doubt, this question required calculations for Market Sizing and Profitability Analysis. You can also expect leading technology companies like Google and Facebook to have quantitative components of interviews for a variety of positions. Mistakes are high-stakes and can cost firms Millions (or even Billions) of dollars when made on the job. Therefore, it’s no surprise that leading firms screen for candidates they believe are unlikely to make mistakes.

Performing calculations in job interviews without calculators or spreadsheets is challenging for many candidates, as calculation skills are not explicitly taught in higher education, including in MBA programs. In fact, calculation skills generally aren’t taught past elementary school. Many students who study quantitative subjects in university say their interview calculation skills are poor —
certainly worse than others expect given their background — because all their math subjects were either purely theoretical or used calculators. Many students with both strong and weak quantitative backgrounds have said that FastMath dramatically improved their calculation skills for job interviews.

For all the formulas taught in your Finance and Economics courses, students have close to zero practice calculating results without electronic aids. Since they likely haven’t explicitly practiced their calculation skills since elementary school, they usually lack the ability to identify realistic (and unrealistic) values for most metrics, so calculation errors regularly slip past undetected. When business school students/graduates do need to perform calculations in interviews (or on the job), they typically apply the same calculation methods an elementary school student would, and so have the calculation “horse-power” of a typical ten-year-old.

In fact, having poor calculation skills is the Achilles Heel for many job candidates, and is one of the most common reasons otherwise-suitable candidates fail job interviews. Many students do lots of company-specific preparation and go into their job interviews feeling confident, only to make a mistake with a seemingly simple calculation. Don’t let your students get caught off guard or fail a job interview because of poor calculation skills — give them access to FastMath!

Efficient Calculation Methods

FastMath interview-prep resources teach a set of efficient calculation methods designed specifically to simplify nearly all calculations required in business interviews. These FastMath calculation methods enable students to perform calculations faster, more efficiently, and with fewer errors, all without using a calculator — as required in most interviews.

 Based on analyzing hundreds of real quantitative interview problems, the FastMath methods are tailored to the specific problems given in real job interviews. FastMath teaches efficient calculation methods for fundamental math operations like multiplication, division, percentages, and compound growth calculations, and for more complex multi-step calculations. FastMath shows students how to re-use intermediate results and thereby find the answer with less effort.

Once students learn FastMath, all the other math they’ve ever learned will seem SLOW!

& Division


Fractions and




Efficient Solutions to Quantitative Interview Problem Types

Students then learn how to apply the FastMath calculation methods to the most important types of quantitative business interview problems such as Breakeven Analysis, Market Sizing and Estimation, Profitability Analysis, Price Optimization, Investment Decision Analysis, and Pipeline/Funnel Analysis. FastMath resources teach students the most efficient solution method for each problem type and provide numerous practice problems with detailed solution methods so that students can sharpen their problem solving skills, and quickly solve these problems when they encounter them in actual job interviews.

Market Sizing
& Estimation




Growth Rate



Economies of


Net Present Value
(NPV) Analysis


Response Rate


FASTMATH is the best quant case preparation resource — hands down! The methods helped me ace my interviews and land a BCG offer!

FASTMATH is essential material you must learn before your job interviews.

Excellent material! FASTMATH definitely helped me land a job at McKinsey!

FASTMATH is easy to learn and highly effective! FASTMATH prepared me for all the quant problems I encountered in interviews.

Quant used to be one of my weakest areas — after learning FASTMATH, now it’s one of my strongest!

A+! FASTMATH is an essential tool for acing consulting interviews!

FASTMATH: The Difference Is Calculation

FastMath is unique among quantitative interview-preparation resources because FastMath teaches students how to perform calculations faster and more efficiently (without using calculators or spreadsheets). In contrast, most other quantitative interview-prep resources simply provide practice problems and answers — without teaching how to actually perform the calculations involved. There are many ex-consultants offering Case Interview prep materials — but there is only one organization that’s 100% focused on math!

FastMath is dedicated to creating best-of-breed quantitative interview-prep resources, and many people believe that mental math (i.e., mental calculation) is the most important, and under-developed, quantitative business skill.

FASTMATH Product Lines

FastMath offers content in two complementary Product Lines (content areas), which each have multiple mediums for students to learn:

FASTMATH Interview Essentials

The FastMath Interview Essentials product line teaches the calculation skills that are essential in business job interviews, where candidates routinely need to calculate Profits (of products, projects, customers, and market segments), Market Sizes, Breakeven Quantities, Profit Margins, Return on Investment, and many other quantitative metrics.

Efficient Calculation Methods

FastMath Interview Essentials teaches fast and efficient calculation methods for essential operations like:

& Division


Fractions and




Quant Problem Types

FastMath Interview Essentials teaches students how to apply the FastMath calculation methods to quickly solve the most common types of quantitative interview problem types:

& Division




Prepare Your Students!

Don’t let your students fail job interviews because their math is SLOW!

FastMath Interview Essentials ensures students are ready for the calculations they will certainly encounter in job interviews and is recommended for all students regardless of industry. Every business school student and graduate should have basic business calculation skills.

FASTMATH Ace the Case

FastMath Ace the Case teaches students the calculation skills needed to succeed in management consulting-style Case Interviews used by consulting firms like Accenture, Bain, and McKinsey, and increasingly in other industries/roles like Product Management and Marketing. FastMath Ace the Case includes all the material from FastMath Interview Essentials and additional material designed specifically for Case Interviews.

Includes All Material from
FastMath Interview Essentials

More Calculation Methods!

FastMath Ace the Case teaches more powerful calculation methods, such as how to efficiently calculate percentage changes in Revenue with Price/Quantity variation, and Margin/Markup calculation methods.

Profit Margoin/



More Quant Problem Types!

FastMath Ace the Case teaches students how to apply FastMath methods to an extensive array of quant Case Interview problem types, and the most efficient solution method for each problem type, so students can quickly solve these problems when encountered in real Case Interviews.



Pipeline Funnel

Rate Analysis



Designed for Case Interviews

FastMath Ace the Case is designed specifically for Case Interviews and is recommended for students interested in Management Consulting, Strategy, Product Management, and Marketing roles.


FASTMATH Delivery Options

Options are complementary and each has unique strengths

There are several ways for students to consume FastMath content, which are listed below. These options are available for both FastMath Interview Essentials and FastMath Ace the Case material.


Workshop Overview

FastMath Workshops are interactive, in-person learning experiences where students learn the FastMath calculation methods and practice applying them to real interview problems. FastMath Workshops are hosted by the FastMath Creator or an expert quant coach.

FastMath Workshops aren’t lectures! After learning and practicing key calculation skills, students work on quantitative problems individually, and then review their solution method in small groups. Finally the instructor will explain the most efficient solution methods for each problem. This process is then repeated for a series of quantitative problems.

In FastMath Workshops, students can ask questions and will receive personalized feedback. Webinars are also available as a substitute for in-person Workshops.

Logistical Details

FastMath Workshops are usually 3.5 – 4 hours in duration (including breaks), and can accommodate up to 120 students per session. If you have more than 120 students, we can always conduct multiple sessions. A large portion of our team is located in Boston, so costs are reduced for Workshops conducted in the northeastern United States.

Learn More

Enter your information below if you are interested in learning more or would like to schedule a FastMath Workshop at your school.


The following schools have hosted FastMath Workshops on calculation skills for job interviews:

Online Courses

FastMath Online Courses primarily use on-demand videos for instruction, and include all the topics covered in the corresponding FastMath Workshop. Instructional style is similar to the Workshop as students solve problems individually, and then learn efficient solution methods — with the benefit of content being available on demand!

FastMath Online Courses have additional lessons (beyond the Workshop material) and include an extensive set of downloadable practice problems with detailed solution methods. FastMath Online Courses reinforce Workshop material and are a great complement to Workshops as well as a great stand-alone resource.

FastMath Online Courses are highly effective because they are available on demand and have a very deep content library. For these reasons many students find the Online Courses to be the most effective way to learn the FastMath methods and material, and certainly complement FastMath Workshops.

On demand!

Extensive content

Internet accessible

Lower cost

Most Effective Delivery Method

Group Purchases

Group purchases of the FastMath Online Courses are available for Career Service offices and student clubs.

Enter your information below to learn more about group purchase options.

Online Courses Subscribers

Subscribers to FastMath Online Courses include students and alumni from the following schools.
The complete list includes nearly every major university worldwide.


FastMath WorkBooks are a new resource, and contain an extensive set of practice problems with detailed solution methods, as well as written explanations of the FastMath calculation methods, diagrams, and reference tables.

FastMath WorkBooks are designed for students to practice their calculation skills directly in the WorkBook. Unlike traditional textbooks, FastMath WorkBooks include detailed solution methods for all included problems.

While much of their content is available as downloadable files in the Online Courses, the WorkBooks are popular because they organize the FastMath material into an easily accessible form factor you can literally take anywhere!

FastMath Workbooks are the best way for students to practice the FastMath methods and improve their calculation skills, and are a great complement to both FastMath Workshops and Online Courses.



Great reference resource

Organize material


FastMath students have joined the following companies (among others):

Partners & Industry Recognition

Leading companies providing business job interview preparation resources recommend FastMath to their customers as a best-of-breed resource to improve mental math and calculation skills for job interviews including: [MBA Case, PrepLounge, Crafting Cases]

FASTMATH: the First and the Best!

FastMath is the first and (many believe) the best resource for improving calculation skills for job interviews.
FastMath resources were designed specifically for the types of calculation required in business job interviews.
Our goal is to be best-in-class in the category of quantitative and calculation skills, which are incredibly
important in job interviews and business.

Students from many different backgrounds have said that FastMath gave them a competitive edge in interviews.

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