Square A No.(100-200) On Finger Tip...

Step 1: Choose the last two digits of the no. and add it to the no.

Step 2: Multiply 100 with the above result.

Step 3: Now Square the last two digits of the no.

Step 4: Add the values obtained in Step 2&3

              This is the required Result.

This Squaring concept is applicable only for three digit numbers from 100 to 200.

For Eg. :-

Consider Squaring 122

Step 1: Choose the last digit of '122' and add it with the given number 122

            =122+22

            =144

Step 2: Multiply 100 with above result 144

            =144 x 100
            =14400
Step 3: Square 22
            =22 x 22
            =484
Step 4: Now, add the values obtained from step 2 and step 3.
            =14400 + 484
            =14884

Hence, Result 
             122 x 122 =14884