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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   Multiplying a 2-digit number by 3 1/3

  1. Select a 2-digit number.
  2. Divide the number by 3.
  3. Move the decimal point one place to the right (or add a zero).

   Example:

  1. The 2-digit number chosen to multiply by 3 1/3 is 78.
  2. Divide by 3: 78/3 = 26
  3. Add a zero: 260
  4. So 78 x 3 1/3 = 260.

   See the pattern?

  1. The 2-digit number chosen to multiply by 3 1/3 is 29.
  2. Divide by 3: 29/3 = 9.6 2/3
  3. Move the decimal point one place to the right: 96 2/3
  4. So 29 x 3 1/3 = 96 2/3.

If the division does not come out even, divide to one decimal place and express the result as a fraction. Your answer will be a mixed number when you move the decimal point one place to the right.


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8 September 1997
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