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Easy problem

  1. Oct 24, 2004 #1

    T@P

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    how can you write an equality ONLY using 2, 3, 4, 5, +, and =? note ALL must be used. I have done this problem and it is easy but i was wondering if there are two ways to do it. Any ideas?
     
  2. jcsd
  3. Oct 24, 2004 #2
    2 + 5 = 3 + 4

    There are infinitely many ways of doing it, providing you don't limit the number of symbols used. I believe this, and rearrangements of this, is the simplest.

    2 + 3 + 4 = 5 + 4

    2 + 2 + 2 + 3 = 4 + 5

    2 + 5 = 3 + 4 = 2 + 2 + 3

    ...

    ad infinitum
     
  4. Oct 25, 2004 #3

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    i believe i misstated the question. the numbers 2 3 4 and 5 can be used only once as with the = and + sign. sorry about that so

    3 + 4 = 2 + 5 would NOT work because you would be using the plus sign twice
     
  5. Oct 25, 2004 #4
    Hmmm, would having two numbers next to each other count as multiplying? For instance 3x is seen as multiplying 3 times the value of x, so could the answer be written 5 + 3 = 2 4 with the statement that 2 and 4 are being multiplied?
     
  6. Oct 25, 2004 #5
    first attempt: 4+5=3²
     
  7. Oct 25, 2004 #6

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    thats what i got too :) but do yuo know any other ways?
     
  8. Oct 26, 2004 #7
    i don't think that there are any more...
    look:
    we have '+' and '=' operators, thus 3 free slots that are to be filled with at least one digit each. so 3 of 4 given didits are bound. that is we have only one free digit left. now, there are not that much possibilities in choosing the numbers for each slot AND choosing the position for the "free" digit. So we can just check all the possibilites for consistency...
     
  9. Oct 26, 2004 #8
    can this equation not be written more appropriately as

    4+5=3^2

    thus we are using more than 2 operators. in fact in this case it is not possible to get an equation as with 2 operators we can use only 3 numbers...........


    thus the only way of using 4 digits would be if we use a 2 digit no. like 24, or 35, or something like that,, but then it is not possible to get any equation. :rofl:
     
  10. Oct 26, 2004 #9

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    im assuming that writing 2^3 on paper by hand would just be the numbers 2 and 3
    if i am not counting operators, just whats written :)

    so anyone know another way? i believe its impossible but i am not sure...
     
  11. Oct 26, 2004 #10

    NoTime

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    In that case 2 4 should be ok also.
     
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