Genady

-

Is 'Zp' the same as 'Z/pZ'?

Are the last three languages North Germanic while Finnish is not?

+1 (when the system lets me.) Replace that remark with, "... if you're not an electron."

I have a question. Before they start with the multiplication, after they learn only addition and subtraction of integers, do they know how to deal with, say, 4-(-6)?

The tables are often turned nowadays. The locals here usually ask visitors, "English, Espanol, Nederlands, Papiamentu?"

+1, but I've used up my daily quota. Will try to remember tomorrow. This option gives integers a ring structure.

Sorry for this impression. I went back and expressed my sincere appreciation of the inputs.

Yes, this is exactly my point, with the emphasis on "has to".

... unless you're a fermion 🙂

Sorry, the link is broken.

What you refer to is, -(-2)=2. It is not intuitive that it has to do with multiplication, i.e., (-1)*(-2)=2.

Interestingly, it seems that it went through the transposition between 'l' and 'r' twice. First, from 'taler' to 'tarel': (тарелка - Wiktionary, the free dictionary) Then it flipped again: (talerka - Wiktionary, the free dictionary)

Well then. The only issue is that this book is aimed at adults as you said rather than at "little children" and thus does not answer the OP question.

Right. It would be a part of the big picture if other operations were presented in this way, too.

An alternative to appealing to symmetries approach could be to uncover what these number operations do to number line: - adding number shifts (translates) the line - multiplying by positive number stretches / compresses the line - multiplying by -1 flips / inverts the line. When the line is flipped / inverted, 2 -> -2, 3 -> -3, ..., and correspondingly, -2 -> 2, -3 -> 3, ... .

"Little children" in my question are school kids which are taught this rule - 3rd grade? As I don't remember any explanation given then to me, I think that there was not one. Like above. Just a rule. I wonder, is it still this way? Everywhere? "Hand waving" explanations like in the book posted by @studiot and the odd-even metaphor recalled by @MigL help perhaps to "get" the rule. How about a "Guess the Rule" game? Let them come up with a possible rule and find that other suggestions don't work?

I also know one word in Finnish: 'talerka', a plate. I remember it from childhood because we had a Finnish set with this word on it and it was funny as it seems to be a misspelled and mispronounced Russian word, 'tarelka' (тарелка), a plate. Now I wonder which way the "misspelling" went and who in fact was dyslexic.

Every language has homonyms. In most cases, they are unambiguous in a context/sentence.

Does anybody know/remember how this rule of number multiplication (see the title) is/was explained to little children?

Perhaps it is so in 'language for tourists' courses. In no language class I've taken I was taught how to ask that.

While the parts with constant relative speed require just algebra, the acceleration and deceleration are more involved. E.g.,

No, there are no such assumptions in science. (With the exception of "etc.", of course.) Demonstrate them.

You haven't demonstrated this kind of bias in science.

The article: 2408.11065 The word 'bias' appears once in the article, in the following paragraph: The next paragraph says,