this post was submitted on 12 Dec 2023
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6÷2(1+2) (programming.dev)
submitted 1 year ago* (last edited 1 year ago) by wischi@programming.dev to c/memes@lemmy.ml
 

https://zeta.one/viral-math/

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 :)

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[–] kuneho@lemmy.world 1 points 1 year ago* (last edited 1 year ago) (10 children)

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.

[–] Spacehooks@reddthat.com 0 points 1 year ago (5 children)

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.

[–] kuneho@lemmy.world 3 points 1 year ago* (last edited 1 year ago) (1 children)

I Looked up doing factorials and n! = n(n – 1) is used interchangeably with n! = n*(n – 1)

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.

[–] SmartmanApps@programming.dev 1 points 1 year ago

there’s absolutely no difference in n(n-1) and n*(n-1)

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 just matter of convenience you can leave it off.

It's a matter of how many terms as to whether it's there or not.

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