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Make 21

  1. Jan 17, 2005 #1
    Make the number 21 using the numbers:
    1, 5, 6, 7

    you can use:
    addition, subtraction, multipliaction and division

    I promise you it is straight forward maths and NO tricks... you can only use each number once and you cant use say 15 (the 1 and the 5 together) and you cant do like 5^6 or anything.
     
  2. jcsd
  3. Jan 17, 2005 #2
    1*.5*6*7 ?
     
  4. Jan 19, 2005 #3
    No TRICKS.

    [tex]\frac{6}{1-\frac{5}{7}}[/tex]
     
  5. Jan 19, 2005 #4

    Galileo

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    Nice :smile:
     
  6. Jan 19, 2005 #5
    wow I was way off, I was not thinking about anything like that at all. good job.
     
  7. Jan 20, 2005 #6
    good work joshm, especially for your first post.
     
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