Trick to find cube roots easily

number	cube
1	1
2	8
3	27
4	64
5	125
6	216
7	343
8	512
9	729
10	1000

number	cube
11	1331
12	1728
13	2197
14	2744
15	3375
16	4096
17	4913
18	5832
19	6859
20	8000

To find cube roots you must know cube roots from at least 1 to 10.

now cube root of perfect cubes can be found out with this method. For numbers which are not a perfect cube, there is another method which I will cover in another blog.


Take any number say

(12167)^1/3

Step 1:  check the last digit of the number whose cube root is to be found

                           1216  7 
             here 7 is last digit .

Step 2: Now go through the list of cubes from 1 to 10 and find out number whose cube has 7 as the last digit.
            So 7 comes as the last digit in the cube of 3 => 2 7 

           So from this, we can say that 3 will be the last digit of the cube root of 12167

Step 3: Now leave last three digits and then take the remaining digits from 12167

            12 /  167

            Now from cubes of 1 to 10 check all cubes and find out the position of 12.
   
            so cube of 2 is 8  and cube of 3 is 27 so consider the biggest number smaller than 12. ie 8                     which is the cube of 2.

           so the first digit of the cube root of 12167 is 2 and the last digit is 3.

                                              So the final answer is 23.


 Similarly, try for other numbers

Key points:   1) always check the last digit first.
                   
                    2) Leave three digits from right to left or from an end of the number and then find out biggest number smaller than that number formed.

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