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10.4: Be aware of a Calculator widget bug
Authored by: cujo on May 24, '05 11:46:51AM

This is not a bug! You don't type 1+2*3 into a single screen on the calc widget. Every time you hit an operator (+,*,-,/, etc) it evaluates the arguments.

This is not complicated. Go pick up any calculator and hit 1+2 and then *. The screen will display 3. Then when you type 3, it multiplies 3*3. This is correct!

It has been said before, but the way calculator.app handles this is misleading and not what the average joe who picks up a standard calculator would expect.



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10.4: Be aware of a Calculator widget bug
Authored by: diamondsw on May 24, '05 12:02:59PM

On all three of my calculators, it properly obeys the order of operations, regardless of what the display shows, which is correct.

This will be my third post saying it - mathematics is not open to your personal preference. It is a very exact discipline, and you are wrong. Find a mathematician (or a third grade teacher - that is when we learned this, after all) and have them explain it to you, if you still think left to right is in any way "correct".



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10.4: Be aware of a Calculator widget bug
Authored by: sdewidt on May 24, '05 01:23:57PM

I think everyone agrees with you on the order of operations. Everyone know "Please excuse my dear aunt sally" or however you learned to remember it. But, I think there are different types of calculators that do things a little differently. I'm, unfortunately, in front of a windows machine right now and I checked out the calc app that is on this machine. Using it in standard mode and typing in the numbers gives me 9, but when I switch it to scientific mode I get 7. I think the calc widget is mimicking one of those cheap calculators that is doing the math step by step instead of considering the numbers as on continuous argument. On those calculators, any time you hit an operator sign, it uses the answer from the step before. In other words, when you type in 1 + 2 and then hit * 3, what the calculator is actually doing it 1 + 2 = 3 * 3 = 9. In my experience this is how most cheap calculators work. I've used a Ti-83 for the last 8-10 years, so I'm just used to typing in all of the numbers on one line and then hitting enter. Anyway, I hope this clears up any problems and misunderstandings.



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10.4: Be aware of a Calculator widget bug
Authored by: csherrera on May 24, '05 02:13:22PM

Look, the calculators you own are obviously designed more recently - I suspect they are scientific or student calculators that understand precedence.

I can't believe how young everyone is on this forum. Am I the only one who remembers that the "cheap, $5 calculators" everyone talks about used to be the $100 calculators not 30 years ago?

When I went to school, precedence was taught as something that you - the mathematician used. It was not something that a calculator figured out for you. If you were presented with the statement 1+2*3= it was up to you to type 2*3+1 to get the correct answer on the calculator. When you did the same calculation on a sliderule, again, you had to do it in the right order.

Look, there is a history to this, these simple calculators follow that historical norm. Just because more modern calculators are smarter, shouldn't obviate the need for YOU to be smart about how you use a tool. Jeez.



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10.4: Be aware of a Calculator widget bug
Authored by: Ol' Codger on May 24, '05 05:28:31PM

You're so right old fellow! These young whippersnappers just don't understand that it's up to them to get it right! Actually the rules they cite, taught to them in the third grade, were intended to teach them how to simplify an arithemetic equation in a multi-step fassion and do not apply to a binary operation calculator. Evaluate everything within parentheses first and rewrite the simplified equation, apply exponents and rewrite the equation, etc.

The common binary operation calculator is only intended to return a result of a binary operation. Given a new operator followed by a operand (number) followed by another operator will generate a new result and allow for chaining calculations in the order they are fed to the calculator, but this in not a strict application of PEMDAS. Then there is RPN which is another beast alltogether.

I'm amused at the author's conviction of the rightness of his assertion. I suggest he not be so adamant and learn how to utilize the tool at hand, or ... get a tool of his liking.



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10.4: Be aware of a Calculator widget bug
Authored by: PeteVerdon on May 24, '05 06:08:16PM

That's what it is!

I definitely fall into the "young" camp as per your "$5 calculator" argument, but the standard calculator at school did operations one at a time like the Dashboard widget. I'm well used to this and, as you say, know what order to put things into it to get the right answer.

On coming to University, my department required that everyone use a *different* "standard" calculator in exams. (No hardship; they sell them for £6 or so). This one has what seems to me a very wierd input system, where you enter the expression and it appears on a series of dot-matrix cells above the main number area, until you press equals and get the answer. I find this awkward to use, wondered why on earth it did that, and generally do one operation at a time as before. But having read this thread I now understand why it's like that - it's trying to do precedence for me, just like it seems other people here are used to. Makes sense, but I still don't like it.

Pete



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10.4: Be aware of a Calculator widget bug
Authored by: itcomesinwaves on May 24, '05 09:28:45PM

"This will be my third post saying it"

..and this is the third time I've cringed reading it. You clearly have missed the point:

- the widget emulates a cheap, non-scientific calculator
- these type of calculators can NOT perform more than one operation at a time
-- (when you press an operator key, it totals the previous operation.)
- this absolves the calculator of any responsibility to obey 'order of operations' because it can only evaluate ONE operation at a time. The responsibility rests with the user to use this "one-operation-at-a-time' tool properly. The order of operations remains unchanged, the calculator works as it is meant to (I.e., with limited scope).


Do you understand now?



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10.4: Be aware of a Calculator widget bug
Authored by: starwxrwx on May 26, '05 02:46:45AM

It's not strictly a bug, but it is a very poor decision by Apple.

Cheap, crappy calculators should be outlawed.

Any decent calculator gets the order of operation correct (which, by the way, is called BIMDAS here in Australia). You should not have to think about the order of operation before typing in your calculation.

Anyone who defends a calculator not doing its job properly (and hence has not passed primary school maths) is not qualified to enter the debate in the first place.



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