To find cube root by estimation we divide a number into two groups and find ones and tens from each group.
Example1):-Estimate cube root of 12167
Here we divide 12167 into two groups 12 and 167
Take 167. we know 3^3=27, a number ending with 7. So for one position, we take the number 3.
Take 12.we know 2^3=8 and 3^3=27 and 8<12< 27. Between 2 and 3, 2 is smaller. So for ten position is 2.
Thus the estimated cube root of 12167 is 23. We can verify the result.23^3=12167
Example 2) estimate cube root of50653
Step1- Divide 50653 into two groups 50 and 653
Step2-First take 653.we know 7^3=343 so for on digit we take 7.
Step3-Now take 50, We know 3^3=27 and 4^3=64. 27<50
so cube root of 50653=37. 37^3=50653. so it is verified.