Calculator won't divide right?

Discussion in 'macOS' started by chainprayer, Sep 12, 2008.

  1. chainprayer macrumors 6502a

    Joined:
    Feb 10, 2008
    #1
    I get this about 3/4 of the time...

    Open calculator and enter -3 / 4.

    Sometimes I get -0.75, but I mostly get 0.75.

    Anyone else get this?

    ...just basic math
     
  2. Xavier macrumors 68020

    Joined:
    Mar 23, 2006
    Location:
    Columbus
    #2
    I get -0.75 every time. Are you sure you're typing it in correctly?
     
  3. siurpeeman macrumors 603

    siurpeeman

    Joined:
    Dec 2, 2006
    Location:
    the OC
    #3
    i also get -0.75 every time. whenever i get an error in the calculator, it's always a user input error for me, but i don't know how you could input -3/4 incorrectly. :confused:
     
  4. pit29 macrumors 6502a

    pit29

    Joined:
    May 23, 2006
    Location:
    The Golden State
    #4
    Are you sure you use the ± button and not the - for making the "-3"?
     
  5. siurpeeman macrumors 603

    siurpeeman

    Joined:
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    the OC
    #5
    it shouldn't matter. if you put minus 3 divide 4, the answer should still pop out as -0.75, because 0-3/4 = 0 - (3/4) = 0 - 0.75 = -0.75
     
  6. BobZune macrumors 6502a

    Joined:
    Oct 26, 2007
    Location:
    USA
    #6
    Interesting - PPC G5 PowerMac here with OS X 10.5.4. For all calculations (that I have checked) that result between 0 and -1, the minus sign is missing on the "calculator display" -- but the internal representation (and if you turn on the paper tape in Window menu) is correct. So if you subtract 1 from the result, you'll get the correct answer (with the minus sign this time). It seems to be a display bug.
     
  7. pit29 macrumors 6502a

    pit29

    Joined:
    May 23, 2006
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    The Golden State
    #7
    I meant: 3-/4 = 3/4 = .75, compared to 3±/4 = (-3)/4 = -.75 ...
     
  8. siurpeeman macrumors 603

    siurpeeman

    Joined:
    Dec 2, 2006
    Location:
    the OC
    #8
    ah, i see what you mean. the op could also hit the plus/minus key before the three. ±3/4 = -0.75
     
  9. sushi Moderator emeritus

    sushi

    Joined:
    Jul 19, 2002
    Location:
    キャンプスワ&#
    #9
    Using the Calculator in Tiger.

    We know that -3/4 = -0.75.

    With the built in calculator, you can enter as:

    --> 3 ± / 4

    --> 0 - 3 / 4

    If on the other hand, if you enter it as:

    --> 3 - / 4 you get 0.75

    The reason is that the calculator interprets the minus sign followed by the divide sign as a correction on the operand. You can see this at the bottom of the display.

    Try this example:

    --> 3 - / x 4 you get 12.

    Basically, you need to use the ± key to enter a negative value.
     
  10. chainprayer thread starter macrumors 6502a

    Joined:
    Feb 10, 2008
  11. sushi Moderator emeritus

    sushi

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    キャンプスワ&#
    #11
    And... ?
     
  12. BobZune macrumors 6502a

    Joined:
    Oct 26, 2007
    Location:
    USA
    #12
    Well, forget division for the moment. What is 1.0 - 1.25 (I get 0.25 on the display, but correct value of -0.25 on the paper tape). You then subtract 1.0 from the result and everything (display and paper tape) are all correct. So it is a calculator 'display' bug (and the internal representation is fine).

    Bug report filed with Apple.

    Thanks for pointing it out, chainprayer - hopefully no one was bitten hard by it.
     
  13. mobilehaathi macrumors G3

    mobilehaathi

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    Location:
    The Anthropocene
    #13
    It is correct for me.
     
  14. brop52 macrumors 68000

    brop52

    Joined:
    Feb 26, 2007
    Location:
    Michigan
    #14
    Same for me
     
  15. sushi Moderator emeritus

    sushi

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    キャンプスワ&#
    #15
    Likewise for me.
     

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