Squaring special numbers (9’s and final 7)

Follow the following Steps:

  1. Choose a number with repeating 9’s and a final 7.
  2. The square is made up of:
    • the same number of 9’s as there are repeating 9’s
    • 4
    • the same number of 0’s as there are 9’s in the square
    • A final 9

   Example-1:

  1. If the number to be squared is 9997:
  2. The square has:same number of 9's as there are
       repeating 9's:              9 9 9
        4                                4
    same number of 0's as 9's
       in the square                       0 0 0
    a final 9                                    9
  3. So 9997 × 9997 = 99940009.
  

   Example-2:

  1. If the number to be squared is 999997:
  2. The square has:same number of 9's as there are
       repeating 9's:        9 9 9 9 9
        4                              4
    same number of 0's as 9's
       in the square                     0 0 0 0 0
    a final 9                                      9

  3. So 999997 × 999997 = 999994000009.