And if you don't then you can no longer claim they are still equal.

This isn’t about limits of accuracy

According to who? Where does it say what it's about? It doesn't.

please show me how basic arithmetic can make 0.999

You still haven't shown why you're limiting yourself to basic arithmetic. There isn't anything at all in the meme to indicate it's about basic arithmetic only. It's just some Maths statements with no context given.

then a correct use of the system must be applicable to everything, right?

Different systems for different applications. Sometimes multiple systems for one problem (e.g. proofs).

You shouldn’t need a new system like algebra to be correct, right?

Limits of accuracy isn't algebra.

You can’t have “a math”

No, you have a branch of Mathematics.

And also if I hadn't been replying to this thread then you wouldn't have got the proof that you were right. :-)

Depends on the system you use

There are no other systems - only people who are following the actual rules of Maths and those who aren't. And yes, 1 is the correct answer

Casio calculators do implicit multiplication first

Actually they follow the actual rules of Maths - Terms and The Distributive Law.

Most maths textbooks This video,

Ignore the video - she completely ignored Maths textbooks (and yes, you're right, the rules are in Maths textbooks - quoted multiple times here).

Right answer, wrong words. The actual rules are Terms and The Distributive Law.

Says who?

The rules of Maths

Not thorough at all. Never once referenced an actual Maths textbook. Read this instead.

Every strata building has a body corporate, and it's nothing to do with seeking power - it's about, you know, collectively running the building. In fact body corporate is a bit of a misnomer, since the word "corporate" comes from the word "corpus", which means "body". More precisely in this context it's a legal body, and may or may not be for-profit (a strata building's body corporate is definitely not-for-profit).