10 Fast Maths Tricks and Shortcuts

Today I am going to summarize all the maths tricks that will speed up your calculation speed. I used them in CAT and IBPS exam. I am sure that these tricks will help you increase your score. I have wrote many articles in detail on these topics. Click on respective links to to get details.

List of Cool Maths Tricks

Squaring

In this simple trick we need to modify the equation and make the units digit zero. After all it is easy to multiply when units digit is zero.

For example - Find square of 43

= (43+3) * (43-3) + (3*3)
=(46*40) + 9
= (460*4) + 9
= 1840 + 9 = 1849

Read my full post on Squaring trick,

Multiplication

Vedic maths gave us the easiest method to do complex multiplications quickly. This method can be quickly explained with an example.

Multiply 62 with 32
Step 1

Step 2

Step 3

Detailed post on Multiplication technique (Multiplication of 3 digit numbers)

Multiplication with 5

Simply multiply the number by 10 and then divide it by 2.
For example 99*5= 990/2= 495

Multiplication with 4

Multiplication with 9

Multiplication with 6

Multiplication with 99

Multiply the number with 100 and then minus same number from the result. Let's take an example
Multiply 32*99 = 3200 - 32 = 3168

Mixture

Questions related to mixtures can be easily solved by alligation method. By using alligation we can wide arrange of maths questions. Let me explain this with a simple example

Example

Price of wine of $60 per liter. If Samuel is adding water with and selling the mixture for $40 per liter. Profit margin remains same. What is the ratio of water and wine in the mixture.

Detailed post on Alligation method (Application on various types of questions)

Square root

Best method to find square root of large numbers is by dividing the number into parts. Let's take an example
Find square √ 1936
√ 1936 = √ 4 * √ 484 = √ 4 * √ 4 * √ 121 = 2*2*11 = 44

Time and Work

Every question in in time and work chapter can be solved easily by finding efficiency of workers or subject (such as pipes).

For example - A takes 10 days to complete a job. B takes 20 days to complete the same job. In how many days they will complete the job if they work together ?
A's efficiency = 100/10 = 10% per day
B's efficiency = 100/20 = 5% per days
A and B can do 15% of the work in a day if they work together. So they can do the whole job in 100/15 = 6.66 days or 6 days and 18 hours.

Detailed post on Time and Work chapter (Practice questions)