In our last post we have learnt how to make the multiplication tables from 1 to 100 in an easy manner. How ever as our kids go to higher grades they need to multiply bigger numbers. In this post today we are going to see how we can do the multiplication quickly and without using the calculator. This becomes extremely useful for children when they have to go for the competitive examination.

**Multiplication by 5**

Lets see how we can easily multiply any number with 5. Example 28×5

Step 1 – divide the number by 2 i.e make 28/2 = 14

Step 2 – Multiply it with 10 so your answer will be 140

Explanation – 5 is half of 10 so when we multiply a number by 5 we are actually multiplying it by 10/2

Lets take another number 25

Step1 – half of the number is ( it will not be a whole number ) 25/2 = 12.5

Step 2 – multiply it with 10 so your answer will be 125

This can be extremely useful when we have to multiply slightly bigger numbers as well.

For example : 122×5 = 122/2= 61×10 =610

**Multiplication by 25**

Lets see how we can multiply a number by 25 quickly

Step 1 : divide the number by 4

Step 2- multiply the number by 100

Explanation: 25 is nothing but 1/4 th of 100 or it can be written as 100/4

lets take couple of examples :

**28×25 **

divide 28 by 4 which is 7

multiply 7 by 100

Answer is 700

Lets take another example

**35×100**

35/4 =8.75 ( 35 when divided by 4 will give answer in decimals)

8.75×100= 875

Lets take one more example

**432×25**

432/4 = 108

108×100= 10800

**Multiplication by 50**

Step 1 : divide the number by 2

Step 2- multiply the number by 100

Explanation: 50 is nothing but 1/2 of 100 or it can be written as 100/2

lets take couple of examples :

88×50

88/2=44 ( divide 88 by 2)

44×100 =4400 is the answer

another example : 762×50

762/2 = 381

381×100

lets take an example where we can not divide the number by 2 and we get the answer in decimal

lets take 35×50

35/2= 17.5

17.5 x 100= 1750

Try out these with few numbers yourself and let us know whether you found this useful. Mail your queries to us on a2yacademy@outlook.com or just leave a comment for us and we will try and bring to you more such tricks to make your life a bit easier.