Kerala PSC - Maths Shortcut Tricks (To find Cubes of 99, 999, 9999)

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Shortcut Method to find out cubes of
(99, 999 and 9999 etc.)

We know that (9)³ = 729 Now we can check how to find out the cube of 99.
To find out (99)³ take 729 as base and Insert a nine before 7 a zero before 2 and again a nine before 9 at last
i.e. 99³ = 970299

To find out (999)³ insert two nines before 7, two zeros before 2 and two nines before 9 at last
i.e. 999³ = 997002999

To find out (9999)³ insert three nine before 7, three zeros before 2 and three nines before 9 at last
i.e. (9999)³ = 999700029999 

∴ (99999)³ = 999970000299999

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