Trick to multiply any number by 19

Lets consider a constant value 

Constant value

0-10 --->1

11-20---->2

21-30--->3

and so on 

How to use...Whenever you see a number like 19x26...how to get result in 1/2 sec... 

Step 1: As you see 26 is somewhere between 20-30 so as mentioned above constant value will be 3 

Step 2: double 26 then minus constant value...example ... here 52-3=49  

So our first 2 digit are 49 and last digit will be the last digit of 19x26 that is 4 

so answer will be 494... It won't take 2 sec if you practice.