Tutorial 51
Squaring numbers in the 100's

  1. Choose a number over 100 (keep it low for practice,
    then go higher when expert).
  2. The last two places will be the square of
    the last two digits (keep any carry) _ _ _ X X.
  3. The first three places will be the number plus
    the last two digits plus any carry: X X X _ _.

   Example:

  1. If the number to be squared is 106:
  2. Square the last two digits (no carry): 6 × 6 = 36: _ _ _ 3 6
  3. Add the last two digits (06) to the number: 106 + 6 = 112: 1 1 2 _ _
  4. So 106 × 106 = 11236.

   See the pattern?

  1. If the number to be squared is 112:
  2. Square the last two digits (keep carry 1): 12 × 12 = 144: _ _ _ 4 4
  3. Add the last two digits (12) plus the carry (1) to the number:
    112 + 12 + 1 = 125: 1 2 5 _ _
  4. So 112 × 112 = 12544.

With a little practice your only limit will be your ability to square the last two digits!