Multiplying a 3-digit number by 99

1. Select a 3-digit number.
2. Subtract the 1st digit plus 1 from the number.
   X X X _ _
3. Subtract the last two digits of the number from 100.
   _ _ _ X X

   Example:

1. The 3-digit number chosen to multiply by 99 is 274.
2. Subtract the 1st digit + 1 from the number:
   274 - 3 = 271 : 2 7 1 _ _
3. Subtract the last two digits from 100:
   100 - 74 = 26: _ _ _ 2 6.
4. So 274 x 99 = 27126.

   See the pattern?

1. The 3-digit number chosen to multiply by 99 is 924.
2. Subtract the 1st digit + 1 from the number:
   924 - 10 = 914 : 9 1 4 _ _
3. Subtract the last two digits from 100:
   100 - 24 = 76: _ _ _ 7 6.
4. So 924 x 99 = 91476.