You can find the square value of any number formed by 1 within two seconds without using calculator. This techniqul is a helpful tool in job written examinations.

Example 01 

11111² ?

Solution Technique

Count how many ones (1) are there. It is 05 ones.

Now write down consecutively  upto five, like 12345

Then from 5, write the digits in reverse order like 4321

Now arrange it: 123454321

That means 11111²  = 123454321

This technique works nice. You need only 2 seconds to spend.