I am going to tell you a method for finding cubes of any number between 21 to 199 in just 3 simple steps and you keep practising then tou will find cube in just 30 seconds.
The one thing you must do is you have to remember the cubes from 2 to 19.
2 : 8
3 : 27
4 : 64
5 : 125
6 : 216
7 : 343
8 : 512
9 : 729
10: 1000
11: 1331
12: 1728
13: 2197
14: 2744
15: 3375
16: 4096
17: 4913
18: 5832
19: 6859
Step 1:
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Consider we have to find cube of 126
(ab)³000
-------x
00000c³
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write the cube of (ab) then write three zeros after that cube..
for example in our number 126, (ab) is 12 and c is 6. So here we write the cube of 12 that is 1728 & cube of 6 like1728000
??????x
0000216
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Step 2:
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Now in the second row, we are gonna put the result of below formula
abc× {(ab)×c×3}
=126×{12×6×3}
=126×216
=27216
1728000
027216x
0000216
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Step 3:
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Now everything has done and it's time to add the numbers of the formula
1728000
027216x
0000216
_______
2000376
so if you like this method, try at home and I am sure you will surprised yourself by doing it in 30 seconds after one or two days of practising.
