0To find cube root of a cubic numbers:
What are cubic numbers
cube of 1= 1, (ends with 1),cube of 11= 1331 (ends with 1), and so on.
cube of 2= 8, (ends with 8),cube of 12= 1728 (ends with 8), and so on.
cube of 3= 27, (ends with 7),cube of 13= 2147 (ends with 7), and so on.
cube of 4= 64,(ends with 8),cube of 148 (ends with 4), and so on...
cube of 5= 125,(ends with 8),cube of 15 (ends with 5), and so on...
cube of 6= 216,(ends with 8),cube of 16 (ends with 6), and so on...
cube of 7= 343,(ends with 8),cube of 17 (ends with 3), and so on...
cube of 8= 512,(ends with 8),cube of 18 (ends with 2), and so on...
cube of 9= 729,(ends with 8),cube of 19 (ends with 9), and so on...
cube of 10= 1000, cube of 20= 8000, cube of 30= 27000, cube of 40 = 64000, and so on.
To find the cube root of a cubic number (lets take the cubic number at most of 6- digits)
1 Take triplets from right.
2 decide the unit place of the cuberoot by looking at the unit place of the cube number.
Unit's place in the cubic number Unit's place in the cubic number
1 1
2 8
3 7
4 4
5 5
6 6
7 3
8 2
9 9
ends with 3 zeros ends with one zero
and so on.
3 decide the 10's place of the cuberoot by looking at the the cube number.
the cubic number(x) Unit's place in the cubic number
0≤x
1000≤x
8000≤x
27000≤x
64000≤x
125000≤x
216000≤x
343000≤x
512000≤x
729000≤x
and so on.
Example-
Find cuberoot of 314432.
314432 ends with 2, so unit place of cuberoot of 314432 is 8.
216000≤314432
So cuberoot of 314432 i= 68.
