Multiplying a 2-digit number by 72

1. Select a 2-digit number.
2. Multiply it by 8.
3. Add one zero.
4. Subtract the first number from the second.

   Example:

1. The 2-digit number chosen to multiply by 72 is 54.
2. Multiply by 8: 54 x 8 = 432
   (Think: (8 x 50) + (8 x 4) = 400 + 32 = 432)
3. Add one zero: 4320
4. Subtract: 4320 - 432 = 3888 (Subtract left to right:
   4320 - 400 - 30 - 2 = 3920 - 30 - 2 = 3890 - 2 = 3888)
5. So 54 x 72 = 3888.

   See the pattern?

1. The 2-digit number chosen to multiply by 72 is 21.
2. Multiply by 8: 21 x 8 = 168
3. Add one zero: 1680
4. Subtract: 1680 - 168 = 1512 (Subtract left to right:
   1680 - 100 - 60 - 8 = 1580 - 60 - 8 = 1520 - 8 = 1512)
5. So 21 x 72 = 1512.

Practice, practice, practice and you will become perfect in your multiplication by 72.