Cube Root Tricks
When we use the term “cube root,” we mean the number that caused the cube to be present underneath the root.
Cube root is a number that need to be multiplied three times to get the original number The radical sign ∛ is used as a cube root symbol for any number with a small 3 written on the top left of the sign.
In Cube root we always get only one answer.
To find cube root we will write down cube root table on paper.
to make it easy.
It is as follow: –
|
Number |
Square of Number |
| (1)3 |
1 |
|
(2)3 |
8 |
| (3)3 |
27 |
|
(4)3 |
64 |
| (5)3 |
125 |
|
(6)3 |
216 |
| (7)3 |
343 |
|
(8)3 |
512 |
| (9)3 |
729 |
|
(10)3 |
1000 |
Than we make a cube root table to find out square root in simple way.
Cube root table is a table of consist in of list of number and their cube roots
|
Digits |
First | Last |
| 4 | 1 |
1 |
|
5 |
2 | 1 |
| 6 | 3 |
1 |
|
7 |
4 | 1 |
| 8 | 5 |
1 |
|
9 |
6 |
1 |
1) If we want to find the cube root of 4 digits than we will consider first and last number.
2) If we want to find the cube root of 5 digits than we will consider first 2 digits and last number.
3) ) If we want to find the cube root of 6 digits than we will consider first 3 digits and last number.
4) ) If we want to find the cube root of 7 digits than we will consider first 4 digits and last number.
5) ) If we want to find the cube root of 8 digits than we will consider first 5 digits and last number.
Like this we will go no increasing the first numbers as digits (radicand) will increase but last digit will be one digit always for cube root.
Here are some example: –
1) ∛6859
This is a 4 digit sum. so here we will consider first and last number.
If we start from last digit than we just have to find 9 or smaller than 9 in the 1 to 10 cube table
It is 729 that is cube root of 9 so we will take 9. This 9 is last digit of final answer.
Then we will take first digit it is 6 and here we have to see smaller digit than 6 in the cube table.
In this table we find 1 smaller number than 6 that is (1)3 =1
19 X 19 X 19= 6859, So final answer is 19.
2) ∛2197
This is a 4 digit sum. so here we will consider first and last number.
If we start from last digit than we just have to find 7 or smaller than 7 in the 1 to 10 cube table
It is 27 that is cube root of 3 so we will take 3. This 3 is last digit of final answer.
Then we will take first digit it is 2 and here we have to see smaller digit than 2 in the cube table.
In this table we find 1 smaller number than 2 that is (1)3 =1
So 13 X 13 X 13= 2197, So final answer is 13
3) ∛17576
This is a 5-digit sum. so here we will consider first two digits and one digit from last.
If we start from last digit than we just have to find 6 or smaller than 9 in the 1 to 10 cube table
It is 216 that is cube root of 6 so we will take 6. This 6 is last digit of final answer.
Then we will take first two it is 17 and here we have to see smaller digit than 17 in the cube table.
In this table we find 8 smaller number than 17 that is (2)3 =8
So we get 2 and 6 that is 26
26 X 26 X 26= 17576, So final answer is 26
4) ∛32768
This is a 5-digit sum. so here we will consider first two digits and one digit from last.
If we start from last digit than we just have to find 8 or smaller than 8 in the 1 to 10 cube table
It is 8 that is cube root of 2 so we will take 2. This 2 is last digit of final answer.
Then we will take first two it is 32 and here we have to see smaller digit than 32 in the cube table.
In this table we find 27 smaller number than 32 that is (3)3 =27
So we get 3 and 2 that is 32
32 X 32 X 32= 32768, So final answer is 32
5) ∛571787
This is a 6-digit sum. so here we will consider first three digits and one digit from last.
If we start from last digit than we just have to find 7 or smaller than 7 in the 1 to 10 cube table
It is 27 that is cube root of 3 so we will take 3. This 3 is last digit of final answer.
Then we will consider first three digits that is 571 and here we have to see smaller digit than 571 in the cube table.
In this table we find 512 smaller number than 571 that is (8)3 =512
So we get 8 and 3 that is 83
83 X 83 X 83=571787, So final answer is 571787
