Important Math Tricks ( Multiplication )

Here are some tips and tricks to be fast in your multiplication .You can use these trick and save time during your exams.But do not try these tricks in the exam without trying them prior to the exam.Hope you will enjoy them.

1.Multiplying by 11

This can be done in two ways.I mostly use the first one as I can quickly do addition.

• First Method-

Imagine that you need to multiply 79 x 11.Here is the trick.What you have to do is multiply 79 by 10 and add another 79 to the answer.

79 x 11 = (79 x 10) + 79 =790 + 79 = 869

• Second Method-

Lets take the same example to this.Leave first and last digits alone and imagine a blank space between them.

79 x 11 =  7( ) 9  

Next step is filling the blank with addition of first and last digits.As you can see it is 16 you have to add first digit of 16 to 7.

79 x 11 = 7 [ 7+9 ] 9 =( 7+1 )69 =769

If you have a larger number the steps are the same.Following example will help you to understand it.

31426 x 11 = 3 [3+1] [1+4] [4+2] [2+6] 6 =  345686

2.Multiplying by 9 

For as an example let's think that we need to multiply 53 x 9.What you have to do is two step process.First step is multiplying 53 by 10.Next step is deducting 53 from the answer.

53 x 9 = (53 x 10) - 53 = 530 - 53 = 477

3.Multiplying by 5

This trick has two different methods.One for an odd number and other for an even number.

• Odd number-

Imagine that you need to multiply 27 by 5.Here is what you need to do.First you need to deduct 1 from the number you need to multiply by 5 and divide it by 2.In here your number is 27.

(27-1) /2 =13

At the end you have to add 5 to the end of your answer.

27 x 5 ={ (27-1)/2 }5 = 135

• Even number-

Here is the process of multiplying even number by 5.Let's take '96 x 5' as the question.What you have to do is very simple.You have to divide your even number by 2 and add a zero(0) at the end of it.

96 x 5 = ( 96/2 ) 0 = 480

4.Multiplying two  number can be written related to hundred       (91 to 99)

Here is the example.Imagine that you need to multiply 92 by 95.Writing numbers related to hundred is this.You can write 92 as ' 100 - 8 ' and 95 as ' 100 - 5 '.In here this process is little bit complicated.But when you configured it  correctly it will be a joyful moment.

• First Step  - 

{92 - ( 100- 95)} or {95 - ( 100- 92} 

*Both give the same answer 87.

• Second Step - 

(100 - 92) x (100 - 95 ) = 8 x 5 = 40

• Third Step - 

 92 x 95 = [answer of first step][answer of second step] = 8740

5.Multiplying a number close to hundred (91 to 99)

Think that you have to multiply 98 by 7. Your steps are followings.

• First step - 

100 x 7 = 700

• Second step - 

700- {7 x ( 100 - 98) } = 700 - 14 = 686

* This can be done only when you are multiplying a number close to hundred by a number   1 to 9.

If you have any extra trick regarding multiplication please comment them in the comment section.