BEATCALC:  Beat the Calculator!

___________________________________________
Back to Calculation Tips & Tricks
___________________________________________

From the BEATCALC mailing list:
a weekly service from B. Lee Clay, archived here by the Math Forum.
To subscribe to the BEATCALC mailing list, write to BEATCALC@aol.com.


   Squaring special numbers (6's and final 8)

  1. Choose a number with repeating 6's and a final 8.
  2. The square is made up of:
    • the same number of 4's as there are repeating 6's in the number;
    • one 6
    • the same number of 2's as repeating 6's;
    • a final 4.

   Example:

  1. If the number to be squared is 6668:
  2. The square has:

    three 4's (same as
       repeating 6's)     4 4 4
    one 6                        6
    three 2's (same number as
       repeating 3's)              2 2 2
    a final 4                            4

  3. So the square of 6668 is 44,462,224.

   See the pattern?

  1. If the number to be squared is 666668:
  2. The square has:

    five 4's (same number as
       repeating 6's)    4 4 4 4 4
    one 6                          6
    five 2's (same number as
       repeating 6's)                2 2 2 2 2
    a final 4                                  4

  3. So So 666668 x 666668 = 444,446,222,224.


webmaster@forum.swarthmore.edu
14 September 1998
Web page design by Sarah Seastone