Multiplication shortcuts - 1

Multiplication of Two digit number with a Single digit number

We've been doing this since the childhood. 32*8

But when it comes to competitive exams there isn't time to do the colum method. You needed step marks when a kid. Not anymore :p

So lets see how to do the multiplication in our mind itself.

Any two digit number 'ab' can be split as (a*10+b). b is the unit's place digit and a is the ten's place digit. When multiplying with a single digit number we split the two digit number like this.

for eg. 32 * 8 =  ( 3* 10 + 2 ) * 8

Now our problem is simplified.

1. First multiply 3 with 8. 8 * 3 = 24.

2. Now put a zero at the end. 240.

3. Multiply 2 with 8. 2 * 8 =16.

4. Add the number obtained now with the previously obtained number.

240 + 16 = 256.

Seeing the four steps one may think, "how hectic is this!"  Try out two questions on your own and you shall find how easy this method is :D

Lets see another example..

Example : -    49*8

49 = ( 4 * 10 )+ 9

1. 4*8 = 32.

2. 320.

3. 9 * 8 = 72

4. 320 + 72 = 392.