Plain Number Math Drills - There are 8 types of Plain Number Math Drills:
In consulting contexts, people like to look at values not only in absolute terms but also relative to each other. Percentage becomes a very useful tool for consulting people. As a consultant, you will very often find yourself doing back-of-the-envelope percentage calculations either in problem solving meetings, in client interviews, or in your own analyses.
Therefore, it is not surprising that this type of calculation is very common in Case Interview and entrance tests (McKinsey PST & BCG Potential Test).
Examples: Work out the following, initially using paperand then try to work out the math mentally once you find the process easy enough.
35% of 40,000?
20% of 1,250?
33% of 2.5 billion?
7.5% of 85?
4% of 1,340?
Hint: If the question is "X % of Y" then the answer is "X multiplied by Y and divided by 100" i.e. (X*Y)/100
Besides addition and subtraction, multiplication is another greatly important building block of calculation fundamentals. Multiplications are not only common in real life but also in every aspect of business and consulting.
Therefore, it is not surprising that this type of calculation is very common in Case Interview and entrance tests (McKinsey PST & BCG Potential Test).
Examples: Solve the Following
4 times 920?
2.5 times 3,400?
85 times 23,000?
2,350 times 8?
350 times 12?
In consulting contexts, people like to look at values not only in absolute terms but also relative to each other. Percentage becomes a very useful tool for consulting people. As a consultant, you will very often find yourself doing back-of-the-envelope percentage calculations either in problem solving meetings, in client interviews, or in your own analyses.
Examples:
900 increased by 54% would be…?
85,200 increased by 6% would be…?
2,400,000 increased by 75 % would be…?
265 increased by 0.2 % would be…?
6,200 increased by 15% would be…?
Hint: The formula is [(X*Y)/100] + X where, X is the amount and Y is the percentage value
Another type of the percentage question.
Examples:
200 decreased by 45% would be…?
73,500 decreased by 8% would be…?
8,500,000 decreased by 35 % would be…?
575 decreased by 0.6 % would be…?
7,400 decreased by 22% would be…?
Hint: The formula is X - [(X*Y)/100] where, X is the amount and Y is the percentage value
The world is getting smaller and international cross-country business is increasingly common. Along with that comes the need to do cross-country currency conversions in real consulting work.
Therefore, it is not surprising that this type of calculation is relatively common in Case Interview and entrance tests (McKinsey PST & BCG Potential Test).
Below are the acceptable rough conversion rates between US Dollars and the 7 most popular currencies in the world as of 2014. These conversion rates are fluctuate from day to day; however, there are still generally-accepted rough estimates in most cases. These estimates are acceptable in Case Interviews unless the interviewer specifically instructs you to use other more precise rates.
Though not very popular in Case Interviews and entrance tests (McKinsey PST & BCG Potential Test), calculations involving time units can be very tricky and time-consuming. Most times, units are easy to imagine and sense but very hard to do calculations with. This is because of their odd nature. There are only 60 but not 100 seconds in a minute, 60 but not 100 minutes in an hour, 24 but not 25 hours in a day, 30 but not 50 days in a month, 52 but not 50 weeks in a year, etc.
A better skill in this very type of calculation will add value to your interviewing and test taking outcome!
In doing these practice calculations, please note that there are two situations regarding hours per week:
Also, assume there are 30 days per month and 365 days per year.
Examples:
120 items per day equal to…items per hour? (24/7)
75,000 items per year equal to…items per week? ( standard work hours)
1,800 USD per month equal to …USD per day? ( standard work hours)
15 items per hour equal to…items per month? ( standard work hours)
25 USD per day equal to…USD per year? (24/7)
When people think of Management Consulting, usually they think of big projects, big clients, and … big numbers. Almost all numbers flying around each project are big: big revenue, big production volume, big FTE (Full-time Equivalent) employees, big investments, big assets, etc. It is essential for all consultants to be comfortable working with big numbers. They have to be able to sense how big “big numbers” are and perform big calculations with them.
Examples:
500 thousand equals to…million?
6400 billion equals to…trillion?
1.5 trillion equals to…thousand?
0.06 trillion equals to…million?
450,000 thousand equals to… million?
