Minus times minus

Can you remember when you first learnt/understood that a negative number times a negative number gave a positive number?

Did you think that makes sense? Did you think it should be negative, or were you just not sure?

I'm sure I'd learnt the rule before then, but I remember working out an explanation for why it makes sense (imagine you give out numbers of merits or demerits to people; taking back a number of demerits is the same as giving that number of merits). Before then, I didn't see why it should be positive, though I don't think I thought it should be be negative, I just didn't understand why.

Conversely, some people think the other way round. Negative Math: How Mathematical Rules Can Be Positively Bent. I haven't read all of his book, so I don't know if it's a good explanation of why and how mathematical rules are chosen, or if he's smoking bad weed. It could be either.

I do know it made me queasy. He seems to think minus times minus giving minus is more obvious, and perhaps should be standard, and that mathematics is a conspiracy against this.

Science fiction concepts done well

I'm reading a book which:

1. Represents a race with below-human intellegence plausibly and sympathetically
2. Represents a race which is portrayed as neither good nor evil, just *different*, though often they might as well be bad, and sometimes good (you know, the elf/old one cliche that gets messed up all the time, but done well)
3. A constructed language used skillfully, introduced naturally and non-jarringly, introducing words for concepts which don't exist exactly in english, and using english "translations" where one is appropriate
4. A mythology which seems internally consistent and emotionally appealing
5. Occasional supernatural effects as a daily part of life, which seem natural
6. Engaging characters
7. Mostly male characters, with some females introduced near the end, and romance portraryed pragmatically and as necessary but not definingly
8. Occasionally moving bits managed to move me
9. Race #1 is the viewpoint. Humanity is race #2.
A. If you haven't guessed, I'm talking about Watership Down. It certainly has flaws -- being able to communicated between species stretches credibility, and he does exagarate the langauge ability of rabbits, and some people hate the plot -- but it's definitely one of my 'must read' list.