Estimating Square Root Of A Number
Step 1: Find the unit digit of square root from the unit digit of given number
Step 2: Discard the last two digits and then check between which two squares the remaining numbers lie.
Unit digit of 256 = 6
Therefore, unit digit of square root = 4 or 6
Discarding 56, remaining digit is 2
1² < 2 < 2²
So 256 must be 14² or 16²
Since we know 15² is 225, we arrive at the solution square root of 256 is 16
Estimating cube root of a cube number
If the cube of 2 is 8, then 2 is said to be the cube root of 8.
If a large number is given and stated that it is a perfect cube then we can use the following method to calculate its cube root by the method of estimation.
Find the cube root of 729