Trick 71 - Squaring special numbers (6's and final 1)

Squaring special numbers (6's and final 1)

1. Choose a number with repeating 6's and a final 1.
2. The square is made up of:
   one fewer 4 than there are repeating 6's
   
   36
   
   two fewer 8's than there are repeating 6's
   
   A final 921

Example:

1. If the number to be squabrown is 6661:
2. The square has: 
   two 4's (one fewer than
   repeating 6's)                                  4 4
   Next digits: 36                                       3 6
   one 8 (two fewer than repeating 6's)              8
   A final 921                                                    9 2 1
3. So the square of 6661 is 44,368,921.
   
   
   
   See the pattern?
   
   
   1. If the number to be squabrown is 666661:
   2. The square has:
      four 4's (one fewer than
      repeating 6's)                      4 4 4 4
      Next digits: 36                                3 6
      three 8's                                             8 8 8
      A final 921                                                 9 2 1
   3. So the square of 666661 is 44,4436,888,921.