In some countries we’re taught to treat implicit multiplications as a block, as if it was surrounded by parenthesis. Not sure what exactly this convention is called, but afaic this shit was never ambiguous here. It is a convention thing, there is no right or wrong as the convention needs to be given first. It is like arguing the spelling of color vs colour.
Firstly, don’t forget exponents come before multiply/divide. More importantly, neither defines wether implied multiplication is a multiply/divide operation or a bracketed operation.
The only confusion I can see is if you intended for the 4 to be an exponent of the 3 and didn’t know how to do that inline, or if you did actually intend for the 4 to be a separate numeral in the same term? And I’m confused because you haven’t used inline notation in a place that doesn’t support exponents of exponents without using inline notation (or a screenshot of it).
As written, which inline would be written as (2^3)4, then it’s 32. If you intended for the 4 to be an exponent, which would be written inline as 2^3^4, then it’s 2^81 (which is equal to whatever that is equal to - my calculator batteries are nearly dead).
we don’t have a standard
We do have a standard, and I told you what it was. The only confusion here is whether you didn’t know how to write that inline or not.
It’s ambiguous because it works both ways, not because we don’t have a standard.
Try reading the whole sentence. There is a standard, I’m not claiming there isn’t. Confusion exists because operating against the standard doesn’t immediately break everything like ignoring brackets would.
Just to make sure we’re on the same page (because different clients render text differently, more ambiguous standards…), what does this text say?
234
It should say 2^3^4; “Two to the power of three to the power of four”. The proper answer is 2⁸¹, but many math interpreters (including Excel, MATLAB, and many students) will instead compute 8⁴, which is quite different.
We have a standard because it’s ambiguous. If there was only one way to do it, we’d just do that, no standard needed. You’d need to go pretty deep into kettle math or group theory to find atypical addition for example.
This is exactly right. It’s not a law of maths in the way that 1+1=2 is a law. It’s a convention of notation.
The vast majority of the time, mathematicians use implicit multiplication (aka multiplication indicated by juxtaposition) at a higher priority than division. This makes sense when you consider something like 1/2x. It’s an extremely common thing to want to write, and it would be a pain in the arse to have to write brackets there every single time. So 1/2x is universally interpreted as 1/(2x), and not (1/2)x, which would be x/2.
The same logic is what’s used here when people arrive at an answer of 1.
If you were to survey a bunch of mathematicians—and I mean people doing academic research in maths, not primary school teachers—you would find the vast majority of them would get to 1. However, you would first have to give a way to do that survey such that they don’t realise the reason they’re being surveyed, because if they realise it’s over a question like this they’ll probably end up saying “it’s deliberately ambiguous in an attempt to start arguments”.
It’s not a law of maths in the way that 1+1=2 is a law
Yes it is, literally! The Distributive Law, and Terms. Also 1+1=2 isn’t a Law, but a definition.
So 1/2x is universally interpreted as 1/(2x)
Correct, Terms - ab=(axb).
people doing academic research in maths, not primary school teachers
Don’t ask either - this is actually taught in Year 7.
if they realise it’s over a question like this they’ll probably end up saying “it’s deliberately ambiguous in an attempt to start arguments”
The university people, who’ve forgotten the rules of Maths, certainly say that, but I doubt Primary School teachers would say that - they teach the first stage of order of operations, without coefficients, then high school teachers teach how to do brackets with coefficients (The Distributive Law).
So are you suggesting that Richard Feynman didn’t “deal with maths a lot”, then? Because there definitely exist examples where he worked within the limitations of the medium he was writing in (namely: writing in places where using bar fractions was not an option) and used juxtaposition for multiplication bound more tightly than division.
Here’s another example, from an advanced mathematics textbook:
Both show the use of juxtaposition taking precedence over division.
I should note that these screenshots are both taken from this video where you can see them with greater context and discussion on the subject.
denotes it with “/” likely to make sure you treat it as a fraction
It’s not the slash which makes it a fraction - in fact that is interpreted as division - but the fact that there is no space between the 2 and the square root - that makes it a single term (therefore we are dividing by the whole term). Terms are separated by operators (2 and the square root NOT separated by anything) and joined by grouping symbols (brackets, fraction bars).
Yep with pen and paper you always write fractions as actual fractions to not confuse yourself, never a division in sight, while with papers you have a page limit to observe. Length of the bars disambiguates precedence which is important because division is not associative; a/(b/c) /= (a/b)/c. “calculate from left to right” type of rules are awkward because they prevent you from arranging stuff freely for readability. None of what he writes there has more than one division in it, chances are that if you see two divisions anywhere in his work he’s using fractional notation.
Multiplication by juxtaposition not binding tightest is something I have only ever heard from Americans citing strange abbreviations as if they were mathematical laws. We were never taught any such procedural stuff in school: If you understand the underlying laws you know what you can do with an expression and what not, it’s the difference between teaching calculation and teaching algebra.
So 1/2x is universally interpreted as 1/(2x), and not (1/2)x, which would be x/2.
Sorry but both my phone calculator and TI-84 calculate 1/2X to be the same thing as X/2. It’s simply evaluating the equation left to right since multiplication and division have equal priorities.
X = 5
Y = 1/2X => (1/2) * X => X/2
Y = 2.5
If you want to see Y = 0.1 you must explicitly add parentheses around the 2X.
Before this thread I have never heard of implicit operations having higher priority than explicit operations, which honestly sounds like 100% bogus anyway.
You are saying that an implied operation has higher priority than one which I am defining as part of the equation with an operator? Bogus. I don’t buy it. Seriously when was this decided?
I am no mathematics expert, but I have taken up to calc 2 and differential equations and never heard this “rule” before.
Sorry but both my phone calculator and TI-84 calculate 1/2X
…and they’re both wrong, because they are disobeying the order of operations rules. Almost all e-calculators are wrong, whereas almost all physical calculators do it correctly (the notable exception being Texas Instruments).
You are saying that an implied operation has higher priority than one which I am defining as part of the equation with an operator? Bogus. I don’t buy it. Seriously when was this decided?
The rules of Terms and The Distributive Law, somewhere between 100-400 years ago, as per Maths textbooks of any age. Operators separate terms.
I am no mathematics expert… never heard this “rule” before.
I’m a High School Maths teacher/tutor, and have taught it many times.
I can say that this is a common thing in engineering. Pretty much everyone I know would treat 1/2x as 1/(2x).
Which does make it a pain when punched into calculators to remember the way we write it is not necessarily the right way to enter it. So when put into matlab or calculators or what have you the number of brackets can become ridiculous.
I’m an engineer. Writing by hand I would always use a fraction. If I had to write this in an email or something (quickly and informally) either the context would have to be there for someone to know which one I meant or I would use brackets. I certainly wouldn’t just wrote 1/2x and expect you to know which one I meant with no additional context or brackets
In some countries we’re taught to treat implicit multiplications as a block, as if it was surrounded by parenthesis. Not sure what exactly this convention is called, but afaic this shit was never ambiguous here. It is a convention thing, there is no right or wrong as the convention needs to be given first. It is like arguing the spelling of color vs colour.
It’s 2 actual rules of Maths - Terms and The Distributive Law.
Correct.
Yes there is - obeying the rules is right, disobeying the rules is wrong.
It’s The Distributive Law
No, it’s an actual rule, and 1 is the only correct answer here - if you got 16 then you didn’t obey the rule.
BDMAS bracket - divide - multiply - add - subtract
BEDMAS: Bracket - Exponent - Divide - Multiply - Add - Subtract
PEMDAS: Parenthesis - Exponent - Multiply - Divide - Add - Subtract
Firstly, don’t forget exponents come before multiply/divide. More importantly, neither defines wether implied multiplication is a multiply/divide operation or a bracketed operation.
The Distributive Law says it’s a bracketed operation. To be precise “expand and simplify”. i.e. a(b+c)=(ab+ac).
Exponents should be the first thing right? Or are we talking the brackets in exponents…
Brackets are ALWAYS first.
Exponents are second, parentheses/brackets are always first. What order you do your exponents in is another ambiguity though.
No it isn’t - top down.
234 is ambiguous. 2(34) is standard practice, but some calculators aren’t that smart and will do (23)4.
It’s ambiguous because it works both ways, not because we don’t have a standard. Confusion is possible.
The only confusion I can see is if you intended for the 4 to be an exponent of the 3 and didn’t know how to do that inline, or if you did actually intend for the 4 to be a separate numeral in the same term? And I’m confused because you haven’t used inline notation in a place that doesn’t support exponents of exponents without using inline notation (or a screenshot of it).
As written, which inline would be written as (2^3)4, then it’s 32. If you intended for the 4 to be an exponent, which would be written inline as 2^3^4, then it’s 2^81 (which is equal to whatever that is equal to - my calculator batteries are nearly dead).
We do have a standard, and I told you what it was. The only confusion here is whether you didn’t know how to write that inline or not.
Try reading the whole sentence. There is a standard, I’m not claiming there isn’t. Confusion exists because operating against the standard doesn’t immediately break everything like ignoring brackets would.
Just to make sure we’re on the same page (because different clients render text differently, more ambiguous standards…), what does this text say?
It should say
2^3^4; “Two to the power of three to the power of four”. The proper answer is 2⁸¹, but many math interpreters (including Excel, MATLAB, and many students) will instead compute 8⁴, which is quite different.We have a standard because it’s ambiguous. If there was only one way to do it, we’d just do that, no standard needed. You’d need to go pretty deep into kettle math or group theory to find atypical addition for example.
This is exactly right. It’s not a law of maths in the way that 1+1=2 is a law. It’s a convention of notation.
The vast majority of the time, mathematicians use implicit multiplication (aka multiplication indicated by juxtaposition) at a higher priority than division. This makes sense when you consider something like 1/2x. It’s an extremely common thing to want to write, and it would be a pain in the arse to have to write brackets there every single time. So 1/2x is universally interpreted as 1/(2x), and not (1/2)x, which would be x/2.
The same logic is what’s used here when people arrive at an answer of 1.
If you were to survey a bunch of mathematicians—and I mean people doing academic research in maths, not primary school teachers—you would find the vast majority of them would get to 1. However, you would first have to give a way to do that survey such that they don’t realise the reason they’re being surveyed, because if they realise it’s over a question like this they’ll probably end up saying “it’s deliberately ambiguous in an attempt to start arguments”.
Yes it is, literally! The Distributive Law, and Terms. Also 1+1=2 isn’t a Law, but a definition.
Correct, Terms - ab=(axb).
Don’t ask either - this is actually taught in Year 7.
The university people, who’ve forgotten the rules of Maths, certainly say that, but I doubt Primary School teachers would say that - they teach the first stage of order of operations, without coefficients, then high school teachers teach how to do brackets with coefficients (The Distributive Law).
The real answer is that anyone who deals with math a lot would never write it this way, but use fractions instead
Yes, they would - it’s the standard way to write a factorised term.
Fractions and division aren’t the same thing.
Are you for real? A fraction is a shorthand for division with stronger (and therefore less ambiguous) order of operations
Yes, I’m a Maths teacher.
I added emphasis to where you nearly had it.
½ is a single term. 1÷2 is 2 terms. Terms are separated by operators (division in this case) and joined by grouping symbols (fraction bars, brackets).
1÷½=2
1÷1÷2=½ (must be done left to right)
Thus 1÷2 and ½ aren’t the same thing (they are equal in simple cases, but not the same thing), but ½ and (1÷2) are the same thing.
So are you suggesting that Richard Feynman didn’t “deal with maths a lot”, then? Because there definitely exist examples where he worked within the limitations of the medium he was writing in (namely: writing in places where using bar fractions was not an option) and used juxtaposition for multiplication bound more tightly than division.
Here’s another example, from an advanced mathematics textbook:
Both show the use of juxtaposition taking precedence over division.
I should note that these screenshots are both taken from this video where you can see them with greater context and discussion on the subject.
It’s called Terms - Terms are separated by operators and joined by grouping symbols. i.e. ab=(axb).
Mind you, Feynmann clearly states this is a fraction, and denotes it with “/” likely to make sure you treat it as a fraction.
It’s not the slash which makes it a fraction - in fact that is interpreted as division - but the fact that there is no space between the 2 and the square root - that makes it a single term (therefore we are dividing by the whole term). Terms are separated by operators (2 and the square root NOT separated by anything) and joined by grouping symbols (brackets, fraction bars).
Yep with pen and paper you always write fractions as actual fractions to not confuse yourself, never a division in sight, while with papers you have a page limit to observe. Length of the bars disambiguates precedence which is important because division is not associative; a/(b/c) /= (a/b)/c. “calculate from left to right” type of rules are awkward because they prevent you from arranging stuff freely for readability. None of what he writes there has more than one division in it, chances are that if you see two divisions anywhere in his work he’s using fractional notation.
Multiplication by juxtaposition not binding tightest is something I have only ever heard from Americans citing strange abbreviations as if they were mathematical laws. We were never taught any such procedural stuff in school: If you understand the underlying laws you know what you can do with an expression and what not, it’s the difference between teaching calculation and teaching algebra.
There is, especially if you’re dividing by a fraction! Division and fractions aren’t the same thing.
Not if it actually is a division and not a fraction. There’s no problem with having multiple divisions in a single expression.
Semantically, yes they are. Syntactically they’re different.
No, they’re not. Terms are separated by operators (division) and joined by grouping operators (fraction bar).
Sorry but both my phone calculator and TI-84 calculate 1/2X to be the same thing as X/2. It’s simply evaluating the equation left to right since multiplication and division have equal priorities.
X = 5
Y = 1/2X => (1/2) * X => X/2
Y = 2.5
If you want to see Y = 0.1 you must explicitly add parentheses around the 2X.
Before this thread I have never heard of implicit operations having higher priority than explicit operations, which honestly sounds like 100% bogus anyway.
You are saying that an implied operation has higher priority than one which I am defining as part of the equation with an operator? Bogus. I don’t buy it. Seriously when was this decided?
I am no mathematics expert, but I have taken up to calc 2 and differential equations and never heard this “rule” before.
…and they’re both wrong, because they are disobeying the order of operations rules. Almost all e-calculators are wrong, whereas almost all physical calculators do it correctly (the notable exception being Texas Instruments).
The rules of Terms and The Distributive Law, somewhere between 100-400 years ago, as per Maths textbooks of any age. Operators separate terms.
I’m a High School Maths teacher/tutor, and have taught it many times.
I can say that this is a common thing in engineering. Pretty much everyone I know would treat 1/2x as 1/(2x).
Which does make it a pain when punched into calculators to remember the way we write it is not necessarily the right way to enter it. So when put into matlab or calculators or what have you the number of brackets can become ridiculous.
I’m an engineer. Writing by hand I would always use a fraction. If I had to write this in an email or something (quickly and informally) either the context would have to be there for someone to know which one I meant or I would use brackets. I certainly wouldn’t just wrote 1/2x and expect you to know which one I meant with no additional context or brackets
By the definition of Terms, ab=(axb), so you most certainly can write that (and Maths textbooks do write that).