[Michael Piziak]

My friend who is a genius at math says the answer to this is 1. Others say it is 36. Even my computers supposed scientific calculator says it's 36.

What gives?


Oh, here's the problem:

48/8(14-8)

Attached Images

 

[luftfluss]

1....

[Not a Number]

It's because the calculator only evaluates operations going left to right. Thus it doesn't evaluate the parentheses until it gets to them.

The correct entry would be:
48 ÷ ( 8 × ( 14 - 8 ) )

Order of precedence for mathematical operations (without parentheses)
Multiplication
Division
Addition
Subtraction
(Mnemonic I learned was "My Dear Aunt Sally")

[Michael Piziak]

It's because the calculator only evaluates operations going left to right. Thus it doesn't evaluate the parentheses until it gets to them.

The correct entry would be:
48 ÷ ( 8 × ( 14 - 8 ) )

Order of precedence for mathematical operations (without parentheses)
Multiplication
Division
Addition
Subtraction
(Mnemonic I learned was "My Dear Aunt Sally")

That's an easy way to learn it ! My dear Autn Sally !

---------- Post added 04-07-23 at 09:19 PM ----------

I've had verification on 2 other sites that I posted this to that the answer is indeed 1.
I also went to a few online scientific calculators that also came up with 36, not all, but enough.

[35mmfilmfan]

It's because the calculator only evaluates operations going left to right. Thus it doesn't evaluate the parentheses until it gets to them.

The correct entry would be:
48 ÷ ( 8 × ( 14 - 8 ) )

Order of precedence for mathematical operations (without parentheses)
Multiplication
Division
Addition
Subtraction
(Mnemonic I learned was "My Dear Aunt Sally")

The one we had at school (ah, memories !) was 'BODMAS'.

This stood for 'Brackets' (self-explanatory); 'Of' (as in 1/4 of 36 - not often used), then as stated. That was about as far as I got - Calculus could just as well have been Martian, for all I could understand !

[Not a Number]

Being nasty kids/teenagers we came up with our own mnemonic: "My Dog Ate (ahem) Something"

[ProfessorBuzz]

My teenager says its "BEDMAS" = Brackets, Exponents, Division, Multiplication, Addition, Subtraction.
What I see is: Messy Bed because she never makes it in the morning.
I'd find another calculator app.

[Lord Lucan]

FWIW, I get 0.05955... when I put in "48/8(14-8)" on my PC's calculator app (kcalc). The inconsistency is due to the user(s) not following the correct input syntax when keying in, so different calculators or apps are interpretting it differently. There should be a multiplying sign in front of the opening bracket, at least I think that is what the formula is meant to be.

[Michael Piziak]

My friend says this about the equation. Then I'm gonna let the thread die:

The full analysis of this situation is now clear: it depends on whether you think like a programmer, or a mathematician. C, and, through its influence over the decades, apparently many other languages as well -- clearly including Perl,as shown here -- is documented and standardized as evaluating expressions left to right, except for performing parenthetical expression evaluation first and bottom-up (or deepest-first). This is just a different rule from what a mathematician or school teacher would consider the proper rules of arithmetic, namely PEMDAS. Clearly, what's happening here is that all the participants in this discussion are programmers, who have grown up WTF commuters, physicians grown up with organic, are accustomed to the C rules and thus really do consider 36 "the right answer" because that's what the official programming language rules give you. However, I submit that, while that is certainly the expected result of the calculation in a organizational language, it is, nonetheless, not the "right answer" that someone who knows how to correctly perform arithmetic should get when doing the calculation "with pencil and paper." Outside of program source code, the rules of PEMDAS are in force and the real-world right answer is 1.The unfortunate fact, though, is that several generations of programmers have now grown up internalizing C-style left-to-right evacuation rules, to the point where they now consistently fail to recognize that exposing that method to the outside would, such as on the display and workings of a calculator app, is a semantic error that muddies the waters and perpetuates and spreads this dangerous misperception.

[Just1MoreDave]

What does the AI think? And can we get two AIs to battle to the death over the answer? That would be useful.

[Michael Piziak]

I'll post this from what my math friend typed, then I'll let others on here argue it out or let the thread die. I posted this in 2 Linux forums and they are already batteling this out, LOL:

I haven't heard anything saying that mathematicians work left to right now, in defiance of PEMDAS. Certainly you work left to right if there's no need for PEMDAS -- no parentheses, no mixing of addition and subtraction, etc. But mathematics, and the rules for evacuating expressions, are one thing that absolutely ought not to change or "evolve over time": the rules need to be rock solid or all of math falls apart.

---------- Post added 04-08-23 at 12:52 PM ----------

I'll add this also:

It depends what source you use. Here multiplication "is of higher precedence than division."

Mixed division and multiplication

In some of the academic literature, multiplication denoted by juxtaposition (also known as implied multiplication) is interpreted as having higher precedence than division, so that 1 ÷ 2n equals 1 ÷ (2n), not (1 ÷ 2)n.[1] For example, the manuscript submission instructions for the Physical Review journals state that multiplication is of higher precedence than division,[20] and this is also the convention observed in prominent physics textbooks such as the Course of Theoretical Physics by Landau and Lifshitz and the Feynman Lectures on Physics.[d]

Source:https://en.wikipedia.org/wiki/Order_of_operations


Using this logic, then the answer would be 1 as multiplication is done first


Regardless, things need to be standardized before a rocket explodes on lift off

[Not a Number]

I was taught multiplication takes precedence over division. Since multiplication is repeated iterations of addition it makes sense since addition takes preference over subtraction. What do I mean repeated iterations?

Multiplication
What is 4 times 3 e.g.:4 × 3 :? 4 + 4 + 4 = 12

Division
How many times does 3 go into 12 e.g.:12 ÷ 3:? 12 - 3 - 3 - 3 - 3 = 0 answer: 4 times

[Michael Piziak]

I have had the following people answer 1 as being the correct answer.

A retired software developer.
A retired professor of mathematics, retired from Baylor University.
My sister, using her sons 4th grade math books as the basis for the rule(s).

One person answered 36 as being the answer, whom is my cousin who is an engineer.

But it seems to me like more people, and perhaps calculators answer 36 (even though the first 2 online Sci. calculators I googled gave 1 as the answer).

Then there are the people online that say the equation/problem is an "illegal" or "ambiguous" equation/problem.

Regardless, am I alone in thinking this could cause a problem, a big problem, in structures being built, rockets being launched, etc.... (?) Or do most of us believe such designers are using plenty of parenthesis to erase all doubt (?)

Addendum: Examples of such problems have occurred, see the post at: https://www.linuxquestions.org/quest...871/page6.html

[Not a Number]

As a programmer I always use parentheses or break the operations down to separate lines of code. Coding can be further complicated with Boolean operations.