Old internet thing. Hotly debated at the time.

https://en.wikipedia.org/wiki/The_dress

I’ll add the contextual link above for others, since it’s been awhile.

Dear colleague,

By qualification I meant explanation. My doctorate is irrelevant to the truth.

Since you asked, my larger point was about the unhelpful nature of this content, which makes students of math feel inordinately inferior or superior hinged entirely on a single point of familiarity. I don’t handle early math education, but many of my students arrive with baggage from it that hinders their progress, leading me to suspect that early math education sometimes discourages students unnecessarily. In particular, these gotcha-style math memes IMO deepen students’ belief that they’re just bad at math. Hence my dislike of them.

Re: Dave Peterson, I’ll need to read more about this debate regarding the history of notation and I’ll search for the “proven rules” you mentioned (proofs mean something very specific to me and I can’t yet imagine what that looks like WRT order of operations).

If what riled you up was my use of the word “conventions” I can use another, but note that conventions aren’t necessarily “optional” when being understood is essential. Where one places a comma in writing can radically change the meaning of a sentence, for example. My greater point however has nothing to do with that. Here I am only concerned about the next generation of maths student and how viral content like this can discourage them unnecessarily.

How are you gonna write 2 + 2 ÷ 2 with repeated addition?

You don't, because the second 2 is associated with a Division that has to be done before the addition. Maybe go back to school and learn how to do Maths 🙄

That doesn’t mean it has to be expanded first.

Yes it does. Everything has to be expanded before you do the addition and subtraction, or you get wrong answers 🙄

2+3x4=2+3+3+3+3=2+12=14 correct

2+3x4=5x4=5+5+5+5=20 wrong

You could expand 2 + 2 × 3 as (2+2)+(2+2)+(2+2)

Says someone who can't tell the difference between (2+2)x3=12 and 2+2x3=8 🙄

you are unable to tell me what mathematical law prohibits it

The order of operations rules 😂

reverse polish notation wouldn’t work as it does

It works because it treats every operation as bracketed without writing the brackets. Also that's only a Maths notation, not the Maths itself.

In RPL, 2 2 + 3 × is 12

Because the way it calculates that is (2+2)x3, not complicated. Same order of operations rules as other Maths notations - just a different way of writing the same thing

If you had to expand multiplication first, how would it work?

It works because Brackets - 2 2 + = (2+2) - are before Multiplication

The same can be done with prefix notation

Another Maths notation, same rules of Maths

Different programming languages have different orders of operations

Maths doesn't

those languages work just fine

They don't actually. Welcome to most e-calcs give wrong answers because the programmers failed to deal with it correctly.

Your argument amounts to saying that it makes the most sense to do multiplication before addition

No, my argument is it's a universal rule of Maths, as found in Maths textbooks 🙄

that only gives you a convention, not a rule

Left to right is a convention (as is not writing the brackets in RPN). Brackets before Multiplication before Addition are rules.