I wrote a (very long) blog post about those viral math problems and am looking for feedback, especially from people who are not convinced that the problem is ambiguous.
It’s about a 30min read so thank you in advance if you really take the time to read it, but I think it’s worth it if you joined such discussions in the past, but I’m probably biased because I wrote it :)
isn’t that division sign I only saw Americans use written like this (÷) means it’s a fraction? so it’s 6÷2, since the divisor (or what is it called in english, the bottom half of the fraction) isn’t in parenthesis, so it would be foolish to put the whole 2(1+2) down there, there’s no reason for that.
so it’s (6/2)*(1+2) which is 3*3 = 9.
the other way around would be 6÷(2(1+2)) if the whole expression is in the divisor and than that’s 1.
tho I’m not really proficient in math, I have eventually failed it in university, but if I remember my teachers correctly, this should be the way. but again, where I live, we never use the ÷ sign, only in elementary school where we divide on paper. instead we use the fraction form, and with that, these kind of seemingly ambiguous expressions doesn’t exist.
The ÷ sign isn’t used by “Americans”, it’s used by small children. As soon as you learn basic mathematical notation in your introductory algebra class, you’ve outgrown the use of that symbol.
Children here in the Netherlands use : as a divisor symbol. I don’t know whether the ÷ sign is particularly American, but it’s not universal.
I don’t know where you’re from, but it’s used universally in Australia - textbooks, calculators, all ages - and from what I’ve seen the U.K. too.
It seems Americans are taught pemdas and not bodas.
I Looked up doing factorials and n! = n(n – 1) is used interchangeably with n! = n*(n – 1)
So Americans will multiply anything first. This is why I put 6 ÷ ( n*(n – 1)) in excel to avoid confusion.
yeah, the way I have been taught is that either you put the multiplication sign there or not, it’s the exact same, there’s absolutely no difference in n(n-1) and n*(n-1). in the end, you treat it like the * sign is there and it’s just matter of convenience you can leave it off.
There is - the first is 1 term and the 2nd is 2 terms. Makes a difference if it’s preceded by a division.
It’s a matter of how many terms as to whether it’s there or not.
deleted by creator
“Next, we perform operations on multiplication or division from left to right.” Found that in like 20 sources. Funny how I didn’t see any of that yesterday.
This is crazy swear never heard that rule.
100% sure I solved everything in class following the acronym. Glad we sorted this out before I helped any kids do Homework.
Yeah, there’s a problem with some lazy textbook authors, which I talked about here. A term is defined as ab=(axb), and yet many textbooks lazily write it as ab=axb, which is fine if that’s the whole expression, but NOT fine if the expression is a/bc (a/(bxc) and a/bxc AREN’T the same thing!), and so we end up with people removing brackets prematurely and getting wrong answers. In other words, in your case, only n!=n(n – 1) and n!=(nx(n – 1)) can be used interchangeably.
No, that means it’s a division. i.e. a÷b. To indicate it’s a fraction it would need to be written as (a÷b). i.e. make it a single term. Terms are separated by operators and joined by grouping symbols (such as brackets or fraction bars).
There is - it’s a single bracketed term, subject to The Distributive Law. i.e. the B in BEDMAS.