• RRB Group D Live Test 4

# Cube and Cube Root

Evaluating Square Roots and Cube Roots in short time is not a cup of tea for everyone. In most of the questions, we usually need to simplify the roots. In this post, we are sharing the Best way to solve square roots and cube roots. Many completive exams like banking, Railways, Central Government, Defense and other government, as well as private vacancies, conducts the Aptitude test. In recruitments test, the quantitative section carries a right amount of weightage to solve the roots. Hence, it is beneficial to learn the trick to solve the square root and cube root i.e. Unitary Method. There are numerous other methods also. However, this one is proved efficient and convenient. We have well explained the concept with the solved examples as well as with the practice questions. To get better speed and accuracy level we advise you all to use the short tricks. Now, let us start discussing the concept.

Square root: Firstly, let’s understand some key points about square root concept.

® A perfect square number is a square number whose perfect under-root exist.

® A perfect square number never ends with 2, 3, 7, and 8

How to find out square root(step by step)?

Step – 1: First of all, look at the unit digit of square number and now check that this is unit digit of which square number.

Here, 6 is unit digit of square of 4 and 6.

Step – 2: Consider the two digit from right hand side. Now, we have to find out nearest perfect square number i.e. 49 which should be less than the number i.e. 57 (left after leaving two digits).

Step – 3: Now we will find out the underroot of that number.

Step – 4: Now we have two option and we have to find out which one is correct.

Note: - Our answer could be 76 or 74 .we have to eliminate the wrong one.

Step-5: To find out which one is correct, we will multiply the number (come from underroot) to its next number (Number come by increasing it by 1).

And check if the result of this is less than the original number (number come after leaving two digits), then higher number will be Prioritize but if the result is greater than the original number. Then smaller number will be taken.

Practice Solved Questions:

Q. 1. How to find the square root of 7921?

Q. 2. How to find the square root of 7921?

Q. 3. How to find square root of 9216?

Q. 4. How to find the square root of 4096?

Cube root: To understand the method,we should know the unit digits of some cube of numbers.

Note: - Unit digit of cube of 1, 4, 5, 6, and 9 is itself the number but the unit digit of cube of 2, 3, 7, and 8 is 8, 7, 3, and 2 respectively.

Steps to find out Cube root --

Step – 1: To find out cube root, we will look at the unit digit of the cube number and we will check that this is unit digit of which cube number.

Note: - Here Unit digit of 412934 is 4 which is unit digit of cube of 4.

Step – 2: Now we will leave 3 digit from R.H.S. and we will find out the cube number less than the number (come after leaving 3-digit)

Note: - Cube root of 343 is 7.

Step –3: Now we will check that this number is cube of which number and place that number (come aftercube root) before with the number (come from last digit).

Solved Practice Questions:

Q. 1. How to find the cube root of 148877?

Sol.1.

Q. 2. How to find the cube root of 50653?

Sol.2.

Q. 3. How to find the cube root of 456533?

Sol.3.

Q. 4. How to find the cube root of 238328?

Hope we are successful in explaining you the entire process. We have given the full description of the method and also explained it step by step. Finding roots quickly is beneficial in increasing speed in the exam. We advise you that you have you practice whatever we taught you in this post. Otherwise, you will not get proficiency in the method. To get the success, you have to practice a lot with consistency. After learning, it is best to analyze yourself, hence for that we have online test series for many topics of quants. If you have queries related to roots problems, then you can ask us by commenting below in the comment section. For more updates stay tuned with us. Thank you!

• ### Test 1

10 Questions
7 Minutes
START FROM: 2017-04-30
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• ### Test 2

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• ### Test 3

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7 Minutes
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• ### Test 4

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• ### Test 5

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7 Minutes
START FROM: 2017-04-30
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