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How to Square A Number With Last Digit 5?

How to Square A Number With Last Digit 5?
In my last post I have shown how to multiply with two numbers without using calculator. This is bit advanced post where I will show to make a square a number having five at last without using a calculator.

Say I have to square 15 that is 15X15=225
How to derive this my using simple calculation:

Step-1
Divide the numbers in the below written manner:


Format the number
Step-2
Draw a line just after 5
Step-2 Draw a line just after 5
Step-3
Multiply 5*5=25 and write it to the right of the bar
Witting first calculation
Step-4
Now add one to the top number here it is 1 so top number becomes 1+1=2

Adding 1 to the top
Step-5

Multiply 2*1(that is the left hand side ..this can be done again with multiply two number method)

Hence the result has come to 225.

Now let us try with a big number called 95X95

As per Step-1 and 2 this will look like-
Step-1

Step-3
Following step -3 we will get 5*5=25

Step-4
Following Step-4 we need to add 1 to the top that is 9 will become 9+1=10

Step-5
As per the final step we need to multiply with 10*9 hence it becomes 90
So 95X95=9025

 
 
















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