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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[–] chuckleslord@lemmy.world 6 points 1 year ago (9 children)

It's covered in the blog, but this is likely due to a bias towards Strong Juxtaposition rules for parentheses rather than Weak. It's common for those who learned math into advanced algebra/ beginning Calc and beyond, since that's the usual method for higher math education. But it isn't "correct", it's one of two standard ways of doing it. The ambiguity in the question is intentional and pervasive.

[–] Portosian@sh.itjust.works 0 points 1 year ago (7 children)

My argument is specifically that using no separation shows intent for which way to interpret and should not default to weak juxtaposition.

Choosing not to use (6/2)(1+2) implies to me to use the only other interpretation.

There's also the difference between 6/2(1+2) and 6/2*(1+2). I think the post has a point for the latter, but not the former.

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

I originally had the same reasoning but came to the opposite conclusion. Multiplication and division have the same precedence, so I read the operations from left to right unless noted otherwise with parentheses. Thus:

6/2=3

3(1+2)=9

For me to read the whole of 2(1+2) as the denominator in a fraction I would expect it to be isolated in parentheses: 6/(2(1+2)).

Reading the blog post, I understand the ambiguity now, but i’m still fascinated that we had the same criticism (no parentheses implies intent) but had opposite conclusions.

[–] SmartmanApps@programming.dev -2 points 1 year ago (1 children)

6/2=3

3(1+2)=9

You just did division before brackets, which goes against order of operations rules.

For me to read the whole of 2(1+2) as the denominator in a fraction

You just need to know The Distributive Law and Terms.

[–] atomicorange@lemmy.world 1 points 1 year ago (1 children)
[–] SmartmanApps@programming.dev -1 points 1 year ago

The linked article is wrong. Read this - has, you know, actual Maths textbook references in it, unlike the article.

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