Monday, February 11, 2013

Pal Multiplication. . .

Wanna multiply 99 with another number, do it simpler as shown below

Any two digit number can be multiplied with 99 in no time. Let us look this with the help of a simple example.

Say you want to multiply 54 and 99. All you need to do is simple subtraction.

We know that :   56  X  99  =  5544 ( by usual multiplication )

Step 1 : Reduce 1 from the number to be multiplied with 99 and find the answer.   56 -1 = 55.
                                   
Step 2 : Subtract the obtained answer from 99 and calculate the balance.  99- 55 = 44 

Step 3 : Place both answers of step 1 and 2 side by side in order, you end up with the product easily.
             Answer = 5544

Here the answers of step one and two are treated as friends and they sit adjacent to each other always and so this multiplication got the name 'pal multiplication'. That was cool ...  :)

Lets look at another case, say 21 is to be multiplied with 99

  1. Firstly subtract 1 from 21.  21-1 = 20.
  2. Now subtract 20 from 99.  99-20 = 79
  3. Product = 2079 ;  Also we know that 21 x 99 = 2079. 

NOTE : Please do remember that this simple technique is useful in calculating 2 digit numbers only.