Guessing a cube root of a perfect cube in 3-5 secs

Hi!  In this post we are going to learn guessing the cube root of a perfect cube in  3-5 secs

first,we will see the cubes of first ten natural numbers if we have this in our mind we can guess cube root of any perfect cube
let me show the beauty of mathematics in cubes 
cube of 2 is 8   and  cube of 8 is ends with 2
and similarly in 3 and 7
and all last digits of the cubes are unique like
1-1
2-8
3-7
4 -4
5-5
6-6
7-3
8-2
9-9
lets  try  an example:   13824
sol: observe the last digit / units digit = 4 that means cube root contains 4 in unit digit
as the given number has 5 digits its cube root will have 2 digits
divide the number in to  parts for every three digits from right to left
13|824
find the nearest cube  to 13 that is 8 its cube root is 2
that’s it. 24 is cube root of the 13824


3 steps 3 secs :-
1) find the unit digit of the number find the unit digit
2) divide the number into parts fro every 3 digits from right to left
3) find the nearest cube to first part of the number
lets try one more example…  373248
sol:
1) unit digit =8 so unit digit of root 2
2)373|248
3) 343 is the nearest cube to 373  cube root of 343 is 7
so 72 is the cube root  that’s it ….hope you like it
(it will applicable up to 6 digits...)

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