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Title: Finding Cube Roots


Autonomous - February 10, 2006 07:53 PM (GMT)
Firstly, you need to memorize the following list, which is very easy.

1=1
2=8
3=27
4=64
5=125
6=216
7=343
8=512
9=729


Now lets try the following example:


√15625=?

The first step is to separate the number 15625 into groups of three from right to left, so:

15 625

Now take the number 15 and compare it to the memorized chart of cubes. You will see that the largest cube which goes into 15 if 2. So the first digit of your answer is a 2. Finally, take the other grouping, 625, and compare it's last digit, 5, to the last digits of the chart. The only option is 125, which is the product 5. So the answer is 25!


√15625=25

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Another example

√941192=?

941 192

The biggest cube that goes into 941 is 9, so the first digit is 9. The other groups last digit is 2. The only cube that ends in 2 is 8. So the last digit in the answer is 8. The number follows as 98.


√941192=98




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