Calculator app bug?

Nutchos

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Jul 21, 2008
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#1
For example if you want to calculate:

(2+2)/4 = 1

You enter into the calculator app(in sequence):

2 + 2 / 4

You get:
2.5

So what it's really doing is:

2 + (2/4)

Where as the regular calculators I've tested with (financial BAII plus, windows calculator) will automatically do:

2 + 2 = 4 / 4 = 1

when you enter in sequence:

2 + 2 / 4 =

This is kinda annoying, especially since I've been writing down wrong answers for the past half hour while trying to do my homework. I'm used to all my calculators auto totaling every time I press =, +, -, etc. Basically, I guess, anytime you're entering a long sequence into the calculator you have to press '=' after every calculation, or keep "orders of operation" in mind.
 

Nutchos

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Jul 21, 2008
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#2
Hmm, looks like it's just the Finance calculators I've been using. My bros scientific calculators and the TI-83plus do it the way iPhone calculator does it. The windows calculator in standard mode will also do it without orders of operation.
 

Youngbinks

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Jun 4, 2007
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#3
Were you actually putting the parentheses around the (2+2)? I just tested it on my calculator app and if you actually put the parentheses then the correct order of operations will prevail.
 

jomaha

New Member
Jul 2, 2007
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#4
The Apps store has a free HP12C (lite) calculator for anyone interested in the RPN format. This format helps users avoid the issue you speak of.
The problem is entered as 2 [enter] 2+ 4/.
To get the other results it's: 2 [enter] 4 / 2+
 

TAEWING59

New Member
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Jul 12, 2008
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#5
just hit the ( or ) button... It cones out to 1 for me if you do that...
 

sdotson

New Member
Aug 25, 2008
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#6
This is because the order of operands is:

Parentheses
Exponents & Roots
Multiplication & Division
Addition & Subtraction

So this is perfectly correct.

If you want (2+2)/4 =1 then you need to enter it this way..
 

sl0ppyshat

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Oct 2, 2007
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#7
This is because the order of operands is:

Parentheses
Exponents & Roots
Multiplication & Division
Addition & Subtraction

So this is perfectly correct.

If you want (2+2)/4 =1 then you need to enter it this way..

agreed....you need the parentheses otherwise the calc is following the order of operations
 

eye-Fone

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Jul 5, 2008
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#8
Break It Down with the Basic Calculator

...if you want to use the basic calculator, you can do this (break the algorithm down into its separate equations):

2 + 2 =
÷ 4 =
That will give you the correct answer.




.
 

psylichon

Genius
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Oct 31, 2007
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Philly
#9
If you reread the original posts, I think the OP is fully aware of order of operations and the equals key workaround. He just wants to be able to put the calculator into "finance" mode that auto-inserts an "equals key" with every command.

Surely there's an app that works this way? Or does Apple not allow them because they compete with the stock calculator?
 
Mar 20, 2009
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#10
BisCal: Standard, RPN, String Input

I'm obviously with sentryapps, and we have recently launched BisCal a businesss calculator in the app store. We have setup the calculator by default to use string mode as I call it. Basically, if you know how the TI-83 or 89 works, that's how ours works. You string out your operators together, and then it calculates the answer.

We are planning on allowing for the standard input method and RPN as settings. Would any of you want to use a calculator that defaults to string, but allows you to change to the other methods? Or do you care?

Thanks for the feedback ahead of time. We devlopers try to spend a lot of time trying to figure what our users want. So thanks for your help!
 

MrMike6by9

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Nov 16, 2008
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#11
I love RPN so much that I bought a second HP-12 to use at work. I started using that method years ago with a HP-41.

YMMV
 

iPhoneMonster

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Jan 18, 2009
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#12
Have you ever heard of BIMDAS? Or Brackets, Indices, Multiplication, Division, Addition, Subtraction? This is a rule which most calculators follow and is taught in most leading junior, senior schools and universities around the world. So you can see that the iPhone is doing the 2/4 first then adding 2. Which is correct mathematics.