Compound Interest short tricks

How to find COMPOUND INTEREST  FOR 

2 YEARS/ 3 YEARS IN MOST SIMPLE WAY

TRICK FOR 2 YEARS COMPOUNDED ANNUALLY

M = RATE * TIME . (Rate)^2

CI = ( PRINCIPAL * M ) / 100

suppose u have to find C.I on Rs. 19000 for 2 years at 6% annually..
                          6*2 . 6^2 = 12.36

now use the formula  (Principal  * 12.36) / 100

the answer is Rs.2348.4


TRICK FOR 3 YEARS COMPOUNDED ANNUALLY

M = RATE * TIME . (RATE^2)*TIME (RATE^3)

CI = (PRINCIPAL * M)/100

                     6 x 3 .  6 x 6 x 3.  6 x 6 x 6
                     18 /108 /  216
                      19.1016 .... ( how this comes..)
explanation -  
                      18 /108 /  216
                      18 / 108+2 / 16
                       18+1 / 10 / 16 
                      19.1016

CI = (19000 * 19.1016)/100 = 3629.304

NOTE--  there is increase of approx.  4 after 10% in 3 years.
you can find the answer using the traditional formula also but this method will reduce your time consumption to great extent.