BEATCALC:  Beat the Calculator!

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Back to Calculation Tips & Tricks
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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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   Dividing a 2-digit number by 375

  1. Select a 2-digit number.
  2. Multiply by 8.
  3. Divide the product by 3 (express remainder as a fraction).
  4. Move the decimal point three places to the left.

   Example:

  1. The number chosen to divide by 375 is 32.
  2. Multiply by 8: 8 x 32 = 240 + 16 = 256
  3. Divide by 3: 256/3 = 85.3 1/3
  4. Move the decimal point 3 places to the left: .0853 1/3
  5. So 32 divided by 375 = .0853 1/3.

   See the pattern?

  1. The number chosen to divide by 375 is 61.
  2. Multiply by 8: 8 x 61 = 480 + 8 = 488
  3. Divide by 3: 488/3 = 162 2/3
  4. Move the decimal point 3 places to the left: .162 2/3
  5. So 61 divided by 375 = .162 2/3.


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21 August 2000
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