Trick 3

My Third trick is -

How to multiply any large number with 12

Example 1 : Consider the multiplication 431 x 12

Step 1 : Starting from right, double to right-most digit. So, we have 1, double it to get 2.

Step 2 : Leaving the unit-digit, double every digit and add the previous digit in the number taking care of the carry-forward in each step.

Step 3 : In the last step, just keep the last digit 4 as it is. This step is very important. You should not double the digit in the last step.