BEATCALC:  Beat the Calculator!

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From the BEATCALC mailing list:
a weekly service from B. Lee Clay, archived here by the Math Forum.
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   Multiplying a 2-digit number by 1 1/8

  1. Multiply the number by 9.
  2. Divide by 8.

   Example:

  1. If the 2-digit number chosen to multiply by 1 1/8 is 32:
  2. Multiply by 9: 9 x 32 = 270 + 18 = 288
  3. Divide by 8: 288/8 = 36
  4. So 32 x 1 1/8 = 36.

   See the pattern?

  1. If the number to be multiplied by 1 1/8 is 71:
  2. Multiply by 9: 9 x 71 = 639
  3. Divide by 8: 639/8 = 79 7/8
  4. So 71 x 1 1/8 = 79 7/8.
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