Find the cube root of 4741632 by estimation.
Answers
First of all observe how many digits are their in the number, then accordingly start your estimation of grouping.
Numbers 1 to 3 give cubes of 1-digit.
Number 4 gives cubes of 2-digits.
Numbers from 5 to 9 give cube of 3-digits.
Numbers from 10 to 21 give cube of 4-digits.
Numbers from 22 to 46 give cube of 5-digits.
Numbers from 47 to 99 give cube of 6-digits.
Numbers from 100 to 215 give cube of 7-digits.
Similarly we categorise the rest of the numbers(and you really have to memories it just like memorising the tables, and squares).
According to your question your number is a 7-digit number.
Therefore it's cube root will be a 3-digit number for sure.
PLUS, the unit's digit is 2, and ONLY NUMBERS ENDING with 8 produce cubes ending with 2.
Therfore, the numbers can be either of 108, 118, 128, 138, 148, 158, 168, 178, 188, or 198.
The given number is 47 lakh something, and if we gamble over the middle numbers instead of going for each number, cube of 150 comes out to be 33 lakh something, cube of 160 turns out to be a little over 40 lakh, BUT cube of 170 will come out to be 49 lakh somethingwhich is much closer to the given number.
Hence we opt for 168, and on cubing 168 we get 47,41,632, which is our number.
Therefore, the answer is 168.
- finding the cube root 4741632
- divide into A and B
