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.
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.
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.
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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.
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.
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.
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.
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.