Excel in mental maths with some easy tricks

Mathematics is one of the most important subjects on which a student’s aptitude is assessed in various exams. Unlike other theory subjects, a full score can be obtained in Mathematics with proper practice. Mostly in all the board exams, it is mandatory for students to show the intermediate steps for all the sums as they are marked on the intermediate steps of a sum. A grip on mental maths always gives students an upper hand in every examination. They can make a quick check of the sums during an examination.

Here are some of the best tricks that will help students improve their mental maths aptitude.

Determining the value of a square root

Determining the square root of any perfect square just takes a couple of minutes. But when it comes to determining the square root of any other number many students falter. The traditional method of determining such square roots is pretty much time-consuming, so here is an easy trick for the same. Let us assume that the question is to determine the square root of 40. The following steps elaborate this method of determining square roots of numbers that are not perfect squares.

Step 1: Find the perfect square that is immediately lower to the given number 40, that is, 36.

Step 2: Add the immediate lower perfect square to the given number, that is, add 36 to 40 for this sum. The obtained result is 76.

Step 3: Find the square root of 36, that is 6.

Step 4: Divide the result of Step-2, that is, 76 by 6. The result so obtained is the required square root.

76/6 = 12.67 

In Vedantu ncert solutions for class 10 maths chapter 2 of polynomials and quadratic polynomials, there are certain sums which require students to find the square roots of various numbers. This trick will make it convenient for them to solve such sums in a short time.

Finding Percentage Values

The concept of percentage is generally introduced in school level academics in the middle section. Initially, students are encouraged to show all the intermediate steps while determining a percentage value. As more advanced concepts are introduced in the higher classes, determining percentage values may be included in other sums as well. In case the percentage values seem to involve a long calculation then this trick of determining such values will be helpful. The below example will elaborate on the same.

Suppose the sum is to determine the quantity that is 6% of 1120. If you notice, the calculation of 6% of 1120, it becomes a lot easier to calculate 1120% off 6. In other words, divide the greater quantity by 100 and then multiply the smaller quantity for such calculations.

Determining the product of 11 and any 2-digit number

There is an easy trick to calculate the product of 11 and a two-digit number, that will save a lot of time during examinations. Suppose the given two-digit number is 31. The following steps will help you understand the method to determine the product of 31 and 11.

Step 1: Find the sum of the digits of the given number, that is, 3+1= 4. 

Step 2: The required product will be obtained by placing ‘4’ (the result obtained in the previous step) in between the two digits of the given number, i.e. 341.

For those two-digit numbers, where the sum of the digits itself is a 2 digit number:

Step 1: Let the given number be 64. The sum of the digits is 10.

Step 2: Now, while you place the obtained sum in between the digits of 64, make sure that you place only the units digit from 10.

Step 3: After placing 0 in between the digits of 64, add the carryover of 1 to 6.

Step 4: The required result is 704.

To check divisibility by 4 and 8

In order to find if a given number is divisible by 2, we check if the unit digit of the number is divisible by 2. But when it is about checking the divisibility of a number by 4, the unit digit cannot help.

For checking the divisibility by 4, we have to check it the last two digits of the given number is divisible by 4. For example, if the given number is 636, then we have to check if 36 is divisible by 4. If it is divisible by 4, then the entire number is divisible by 4.

For checking the divisibility by 8, we have to check if the last three digits of the given number are divisible by 8. For example, if the given number is 5864, then we have to check if 864 is divisible by 8. If 864 is divisible by 8, then the entire number is divisible by 8.

Knowing such tricks for mental maths, helps students speed up with their calculations during any examination. The above-mentioned tricks will certainly help students to improve their calculation skills and secure good marks in their Maths examination.