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 68030

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

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.

4. pit29 macrumors 6502a

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

Joined:
Dec 2, 2006
Location:
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

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

8. siurpeeman macrumors 603

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

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.

Joined:
Feb 10, 2008

Joined:
Jul 19, 2002
Location:
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

Joined:
Aug 19, 2008
Location:
The Anthropocene
#13
It is correct for me.

Joined:
Feb 26, 2007
Location:
Michigan
#14
Same for me

15. sushi Moderator emeritus

Joined:
Jul 19, 2002
Location:
キャンプスワ&#
#15
Likewise for me.