Squaring the number ending with 5

Hard to remember the squares of the numbers????

A simple technique which helps you to need not remember the square of the number ending with 5 will be explained here...

Let me explain this technique with a simple example..

let us find the square of a number 35

1. First the square of the 5 is written in the units digit and tens digit viz. 25
2. Now multiply the number 3 with (3+1) i.e we need to find 3*(3+1) and write the result before 25 and we get the result as 1225

Now let us generalize this 
     If the number is of the form 'a5' and we need to find the square of that number then the result will be a(a+1)25

This method can also be extended to multiply two numbers whose sum of the unit's digit will be 10 and the remaining digit are same.
If the two numbers are 'ab' and 'ac' where b+c=10 then
Units and tens digit will be the units and tens digit of the product b*c and the remaining digits will be the product of a(a+1)

Let us understand this with an example..

Product of 13 and 17

As stated from the above technique

• The units and tens digit will be the product of 7 and 3 i.e 7*3=21
• The remaining digits will be the product of  1(1+1)=02
• Thus the product of 13 and 17 is 0221