Just the word “Math” brings trouble and tension for certain students as it contains chapters like vectors, trigonometry, etc. Even if you had let out a great big sigh of relief when you got out of school, you soon would have realized that it is much needed in our day to day life. Whether you are a math lover or despise it, the following tricks and shortcut methods will help to speed up calculations and turn you into a math whiz.
Power multiplication or squares of a number ending with 5
The speed of this trick would amaze you. Find the square of 85 mentally, how much time would you normally take? Now try this trick.
- Ignore the 5 present in the units place.
- Take the digit present in the tens place (i.e) 8 and multiplying it with its successor (i.e 8+1 = 9) we get 72.
- Place 25 at the end of the result we get 7225.
Hence, we get 7225 as the result of squaring 85.
This fast trick can be used to find the square of any number that ends with 5. It is also effective for three digit numbers as well. Example: Find the square of 135,
- Multiply 13 with its successor (i.e 14) which results to 182
- Now adding 25 to the end, results in the answer 18225
Hence, we get the answer for 3 digit numbers as well.
Multiplication with 5
A fast trick to do these type of calculations is that, if a number is to be multiplied by 5 it is the same as multiplying the number by 10 and dividing its result by 2. So, here is the trick. If 236 is to be multiplied with 5
- Divide 236 by 2 i.e. 118
- Now add 0 to its end and the answer is 1180
Hence, we get 1180 as the result of multiplying 236 with 5.
If the number is a decimal, the trick still can be used. Try and multiply 1305 with 5.
- Divide 1305 by 2 i.e 652.5
- Now the result is multiplied by 10 and we get 6525
Multiplication with 9
This shortcut trick will help us solve calculations with multiplications of 9 in a much simpler method. This method is essential if you are fast with subtraction. Say you have to multiply 81 with 9
- Add 0 to the end of the number, i.e. 810
- Subtract the initial number with the number i.e. 810 – 81 = 729
This trick works every time although gets a little cumbersome when mid-sized numbers are dealt with. This shortcut will help to solve multiplications of 9 much faster.
Multiplication with 15
15 can be written as 10 + half of 10. So if it has to be multiplied by any number then this trick will definitely help your arithmetic computation speed. If 67 is to be multiplied by 15,
- 0 should be written at the end of the number. We get, 670.
- Divide the new number (i.e. 670) by 2. We get 335
- Adding of the two numbers we get 335 + 670 = 1005
Hence we get the result using this shortcut when a number is to be multiplied by 15.
Division with 5
So far we saw multiplication tricks; here is a fast trick to do calculations if a number is to be divided by 5. Say you want 565 to be divided with 5
- Multiply 565 by 2 i.e. 1130
- Now move the decimal point one to the left and reduce one 0 and the answer is 113
Hence, we get 113 as the result of dividing 565 with 5.
This trick works with decimals as well, just say 142.3 is to be divided by 5.
- Multiply 142.5 by 2 i.e 284.6
- Now the result is divided by 10 and the decimal point is moved one position towards the left. We get the result as 46
The main thing to understand about these basic tricks is nothing actually but the application of basic mathematical rules. Tricks are okay and helpful but the main focus needed to improve your calculation speed is a practice which helps you get faster and more interested. And the best way to boost your calculations is by boosting your familiarities with numbers. These tricks and shortcuts will help the students to score well in their CBSE examinations.
For a better understanding of concepts and more tips and tricks to help calculations to be done easily, the candidates can subscribe to our Byju’s YouTube Channel like Mathematics apps.