More often than not, my students ask me how I did certain calculation so quickly without any calculator or pen and paper. Today, allow me to share certain calculation shortcuts.

• Percentage Calculation: The quickest way to calculate percentages is to multiply the numbers first and divide by 100

Example: 30% of 50 are 15.

In the event that these are not whole numbers round them up to the nearest whole number and deduct an approximate value.

• Square Roots: A very quick approximation is possible if you know by heart certain squares

Example: if we want to know the square root of 150. We know that the square of 12 is 144 and 13 is 169. Therefore 150 would be closer to 12. So one can approximate to 12.2.

• Hourly rate calculation: If you are poised with a question of which is better - an annual salary of 90,000 INR or an hourly salary of 49 INR, the simplest step is to remove the 3 zeroes at the end and divide the remaining by 2. Therefore in this case, 90/2 gives 45. Therefore an hourly salary of 49 is better.

• Average: If you are to find the least amount needed to make an average of 50 from

1.        45

2.        52

3.        48

4.        56

Simply calculate the difference to reach the target, in this case it would be

-5+2-2+6 this will be +1. Therefore the next needed value is 49.


Here at MathsOne Academy, one of the Top Maths Tuition Centers in Kerala, we teach our students these subtle tricks that would help them a lot.