In the previous article, we learnt about division by numbers ending in 9. It's ok if you need exact value, like what I calculated for 1/19. But for JEE, approximate value of 1/19 = 0.05263 may do.
How do you plan to do it? Divide by 19 everytime? No... you don't need to learn tables of 19. How about dividing by 2 or 5 or such small numbers!
We will make use of previous sutra - by one more than the previous one.
Let's start with 1/19 as example, followed be 1/7.
one more than the previous one for 19 is 2. So, we would divide all the way by 2.
1 divided by 2 gives 0 as quotient and 1 remainder.
1/2 = 0.10
Now, we divide 10 = 10 by 2 to get 5 as quotient and 0 as remainder.
0.10 => 0.005
Now, we divide 05 = 5 by 2 to get 2 as quotient and 1 as remainder.
0.10 => 0.005 => 0.0512
Similarly, the full calculations yields:
0.0512 => 0.05206
=> 0.052603
=> 0.0526311
=> 0.05263115
... and so on.
The advantage of this method is that you can stop whenever you feel you are ok with the precision of the result. For example, you can stop at 0.053 as an approximation or at 0.05263.
We shall carry the direct calculation for 1/7 = 7/49 where divisor is 4 + 1 = 5. We will start by dividing 7 by 5.
7/49 => 0.21
=> 0.114
=> 0.1442
=> 0.14228
... and so on!
Kewl... ain't. Note that all these tricks that I have been telling you till now are what I learnt in "Vedic Mathematics".
