Multiplication comes before division in some forms, like PEMDAS. In the example I use, this changes the answer

If you have both multiplication and division then you do them left to right. PEMDAS doesn't mean multiplication first, nor does BEDMAS mean division first. It's PE(MD)(AS) and BE(DM)(AS) where the bracketed parts are done left to right.

you should specify what it is operating on

Left associativity means it always operates on the following term. i.e. terms are associated with the sign on their left.

The minus sign only applies to the middle term, by convention

By the rule of left associativity.

But if you use one of these acronyms, you end with this expression evaluating to -2

No it doesn't. How on Earth did you manage to get -2?

all these acronyms end up being useless waste of time

No they're not, but I don't know yet where you're going wrong with them without seeing your working out.

Implied multiplication coming before explicit multiplication/division is what’s recent.

1. "implicit multiplication" is not taught, because there's no such thing as implicit multiplication
2. the "controversy" over it isn't recent either - we can see Lennes complaining about it more than 100 years ago! The more things change the more they stay the same (sigh).

you’re in for a surprise

I'm not actually. A lot of people don't want to confront evidence that they're wrong.

She didn’t reference any math textbooks because she made the video for commoners, aka not math majors.

Did you notice she's a Physics major? In other words, she doesn't have any Maths textbooks to reference.

Her explanations make sense

So, even when she couldn't explain why one calculator "sometimes obeys juxtaposition, sometimes doesn't", that still made sense to you?

technically wrong

Bingo!

I don’t think many people are going to see your reply

These comments are going to show up in search results for the rest of eternity, so I'm quite happy to debunk the disinformation in it.

you seem to have copy/pasted the reply on several comments

3 different people referred to the same video, so yeah I did something I don't normally do and copy/pasted for those 3 people. Read my other replies and you'll find they're all specific to the person I'm replying to.

It’s like you searched for the YouTube link

No, I've had multiple people tell me about it previously, as "proof" that Maths is ambiguous, hence why I wrote a thread debunking the claims she (and others) made.

It just seems suspect

It's all legit, so feel free to go back and read what I've written given that context.

the whole issue can be avoided

...by following all the order of operations rules

You know sometimes both are correct

Nope. That's what the order of operations rules take care of.

Schools only started teaching that rule relatively recently

Recently? The order of operations rules have been taught for more than a century (we can see them in Lennes' letter).

Makes my programmer brain hurt when there’s no consistency and a lot of implicit rules.

All the order of operations rules of Maths are explicit

I’m with the right answer here

Apparently not.

if you wanted to treat 2(2+2) as a single unit

Yes, it is a Term subject to The Distributive Law, written just the way it is.

Knowing the rules of Maths means someone might be drunk? Interesting conclusion.

Yes

No.

8 / 2 (4) 8/(2x4) 8/8 1

there is no standard order of operations across languages

Yes there is. The rules of Maths are universal.

It’s an easy place for bugs to sneak in

But that's because of programmers not checking the rules of Maths first.

What’s |a|b|c|?

The absolute value of a, times b, times the absolute value of c (which would be more naturally written as b|ac|). Unlike brackets, there's no such thing as nested absolute value. If you wanted it to read as the absolute value of (a times the absolute value of b times c), then that's EXACTLY the same answer as the absolute value of (a times b times c), which is why nested absolute values make no sense - you only have to take absolute value once to get rid of all the contained signs.