Method to calculate the Square of the numbers with the unit digit 1

 Inorder to calculate the square of the numbers with their unit digit " 1", just add the square of the previous number, the previous number and the number given.

For example, 

11 ^ 2 = 10 ^ 2  + 10 + 11 = 100 + 10 + 11 = 121
91 ^ 2 = 90 ^ 2  + 90 + 91 = 8100 + 90 + 91 = 8281


Thanks, Numbersmania -Where MATHS is Life Facebook Page.