1. Choose a number with a 9 and repeating 3's (use at least three 3's).
2. The square is made up of:
   • first digits: 87 & two fewer 1's than repeating 3's
   • next digits: 04 & one fewer 8 than repeating 3's
   • last digit: 9

   Example:

1. If the number to be squared is 9333:
2. The square has:

   first digits: 87 and two fewer
    1's than 3's                8 7 1
next digits: 04 and one fewer
    8 than 4's                        0 4 8 8
last digit: 9                                 9

3. So 9333 × 9333 = 87,104,889.

   See the pattern?

1. If the number to be squared is 933333:
2. The square has:

   first digits: 87 and two fewer
   1's than 3's           8 7 1 1 1
next digits: 04 and one fewer
   8 than 3's                      0 4 8 8 8 8
last digit: 9                                  9

3. So 933333 × 933333 = 871,110,488,889.