this post was submitted on 03 Dec 2023
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My Casio calculators get this wrong, even the newer ones. BTW the correct answer is 16, right?
(8 ÷ 2) × (2 + 2)8 ÷ (2 × (2 + 2))2 2 + 8 2 ÷ × .(× (÷ 8 2) (+ 2 2))prefix notation doesn't need parentheses either though, at least in this case. lisp uses them for readability and to get multiple arity operators. infix doesn't have any ambiguity either if you parenthesize all operations like that.
There isn't any ambiguity even if you don't.
You added brackets and changed the answer. 2(2+2) is a single term, and if you break it up then you change the answer (because now the (2+2) is in the numerator instead of in the denominator).
The only right answer
Nope, 1 is the only correct answer.
Except they don't. This isn't a notation problem, it's a people don't remember the rules of Maths problem.
PEMDAS is actually (PE)(MD)(AS). Those that are grouped together have equal precedence and are evaluated left to right.
8 / 2 * (2+2)
8 / 2 * 4
4 * 4
16
Edit to fix formatting, maybe?
When you added the multiply you changed the answer, because the (2+2) is now in the numerator instead of in the denominator.
Yes
8 / 2 (2+2)
8 / 2 (4)
4 (4)
16
No
8 / 2 (2+2)
8 / 2 (4)
8 / 8
1
No. Order of operations is left to right, not right to left. 1 is wrong.
Pemdas.
Multiplication comes before division.
1 is the correct answer.
That's wrong. Multiplication and division have equal precedence, same as addition and subtraction. You do them left to right. PEMDAS could be rewritten like PE(MD)(AS). After parentheses and exponents, it"s Multiplication and division together, then addition and subtraction together. They also teach BODMAS some places, which is "brackets, order, division and multiplication, addition and subtraction" Despite reversing the division and multiplication, it doesn't change the order of operations. They have the same priority, so they are just done left to right. PEMDAS and BODMAS are the different shorthand for the same order of operations.
They were right but for the wrong reason. Implied multiplication–that is, a(b) or ab–often comes before explicit multiplication and division. Apparently it's up to the person writing the equation, so the meme is intentionally and explicitly ambiguous
They're still wrong, in my humble opinion. I'm aware of this notion, and I've even had people share a snip from some book that states this as fact. However, this is not standardized and without the convention being widely understood and recognized as the standard in the world of mathematics (which generally doesn't use the symbol (÷) at all at post-algebra levels), there is no reason to treat it as such just because a few people assert it is should be.
It doesn't make sense at all to me that implied multiplication would be treated any differently, let alone at a higher priority, than explicit multiplication. They're both the same operation, just with different notations, the former of which we use as shorthand.
There are obviously examples that show the use of the division symbol without parentheses sometimes leads to misunderstandings like this. It's why that symbol is not used by real mathematicians at all. It is just abundantly more clear what you're saying if you use the fraction bar notation (the line with numerator on top and denominator on bottom). But the rules as actually written, when followed, only reach one conclusion for this problem and others like it. x÷y(z) is the SAME as x÷y*z. There's no mathematical or logical reason to treat it differently. If you meant for the implicit multiplication to have priority it should be in parentheses, x÷(y(z)), or written with the fraction bar notation.
Implicit multiplication being before regular multiplication/division is so we can write 2y/3x instead of (2y)/(3x). Without priority, 2y/3x becomes (2y÷3)•x.
Coefficients are widely used enough that mathematicians don't want to write parentheses around every single one. So implicit multiplication gets priority.
I think one could argue a coefficient on an unknown variable, like 2y, should take higher priority simply because it cannot be any further resolved or simplified. That is not the case with, say, 2(3+1). Although that does still leave you with potential ambiguity with division/multiplication, such has 1/7y. Is the coefficient 7, or is it 1/7? i.e. Is that 1/(7y)? Or (1/7)y? Either way, if that's not the the standard understood by everyone, then it is a non-standard, inconsistent rule. And as demonstrated, if you do use that rule, it needs to be more clearly defined. That is the source of this "ambiguity". If you don't include it, the order of operations rules, as written, are clear.
Bingo!
It's the same thing, where y=3+1.
Yes, it's 1/(7y) as per the definition of Terms.
It's the standard in literally every Maths textbook.
There's an argument to be made that implicit multiplication comes before division, resulting in the answer 1, but all multiplication? That's wrong, full-stop. You calculate (explicit) multiplication and division in one step, left to right. Reason being that division is technically just multiplying by the reciprocal.
a(b) is a×b. Step 2 could be rewritten as 8 / 2 × 4. Working left to right, step 3 becomes 4 × 4.
No, because implicit multiplication binds more tightly than explicit. a/b(c) becomes a/(b×(c))
Says who?
Most maths textbooks written by mathematicians.
I don't mean when they're explaining "here's how the order of operations works". I mean in the basic way that they write more advanced problems and the answers they give for them.
This video, and the prequel to it linked in the description, go into some detail showing who uses what convention and why.
Interestingly I’ve wondered if this is regional, as a fellow Aussie I learned the same as you but it seems in other places they learn the other way
FWIW I went to school in Asia, using an internationally-focused curriculum, rather than going through the Australian curriculum here in Aus.
The video I linked includes some discussion with a calculator manufacturer who apparently is under the impression that teachers in North America are asking for strict BIDMAS, so the calculator manufacturer actually switched their calculators to doing that. Until they then got blowback from the rest of the world's teachers, so they switched back to BIDMAS with juxtaposition being prioritised over division. The video also presents the case that outside of teachers—among actual maths and physics academics—prioritising juxtaposition is always preferred, even in North America.
Huh, I'll be darned. I'm not as much of a math nerd as I thought
Here is an alternative Piped link(s):
This video
Piped is a privacy-respecting open-source alternative frontend to YouTube.
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The rules of Maths
That's exactly where the calculators in the op differ. For more examples, Casio calculators do implicit multiplication first, while ti's treat it the same as explicit multiplication and division. I think that the latter is more predictable personally, but really you just need to know your calculator.
Actually they follow the actual rules of Maths - Terms and The Distributive Law.
Right answer, wrong words. The actual rules are Terms and The Distributive Law.
No.
8 / 2 (4) 8/(2x4) 8/8 1
That's (2x4). Doing division before brackets goes against the order of operations rules.
I didn't say they weren't. I said...
You did 8/2x4, which is the same as (8/2)(2+2), which isn't the same as 8/2(2+2)=8/2(4)=8/(2x4).
No, as I already pointed out, it's the same as (2x4). You can't remove brackets unless there is only 1 term left inside. 2x4 is 2 terms, so can't remove brackets yet.
BWAHAHAHA! 😂 Google gets it wrong too. Try looking in a Maths textbook instead (I have plenty of them since I'm a Maths teacher).
Also Google...
No, the correct answer is 1.
Depends on the system you use. Most common system worldwide and in the academic circles (the oldest of the two) has 1 as the answer.
There are no other systems - only people who are following the actual rules of Maths and those who aren't. And yes, 1 is the correct answer