04.11 Multiply any number by 12

To multiply any number by 12 

To multiply any number by 12 just

double last digit and thereafter

double each digit and add it to its

RHS neighbour. 

if we get carry and add carry after the doubling the number.

For example 

21314 * 12 =  255768 

Lets break it into simple steps: 

Step 1: 021314 * 12 

(Double of Last Digit 4= 8 ) 

=  _____8 

Step 2: 021314 * 12 

(Now Double 1= 2, and add it to its RHS 4, 2+4=6) 

=  ____68 

Step 3: 021314 * 12

(Now Double 3=6, and add it to 1, 6+1=7) 

=   ___768 

Step 4: 021314 * 12

(Now Double 1=2, and add it to 3, 2+3=5) 

=   __5768 

Step 5: 021314 * 12

(Now Double  2=4, and add it to 1,

4+1=5) 

=   _55768 

Step 6: 021314 * 12

(Now Double 0=0, and add it to 2,

0+2=2) 

=   255768 

So your final answer of 

21314 * 12 = 255768

Ex. 09 × 12 = 108

Ex. 13 × 12 = 

013 =         156

Ex. 1423 × 12 = 

01423 =         17¹076

Ex. 078456 × 12 = 

078456 =        9²4²1¹4¹7¹2