Multiply a number by 4

Multiply a number by 4:

It may be easy to multiply a number by 4 using the tables. But for a long integer it would be difficult to multiply it by 4.
Hence we need a calculator to perform the task.

So use this shortcut to multiply by 4.
* Multiply the number by 2.
* Again double it you will get the answer.

For example,
if you want to multiply 16 by 4.
* first double the number by 2(16*2=32)
* again double it by 2(32*2=64)

That's it.. you got the result......