# Tables in -5

1. Jun 19, 2004

### 1+1=1

i am curious as to how this would look. i wonder how the addition tables would look in base -5? would the multiplication look the same?

here is what i know so far:

0 1 2 3 4 0 0 0 0 0
1 2 3 4 10 0 1 2 3 4
2 3 4 10 11 0 2 4 11 13
3 4 10 11 12 0 3 11 14 22
4 10 11 12 13 0 4 13 22 31

i know this, but where are the negative signs at??

Last edited: Jun 19, 2004
2. Jun 19, 2004

### geraldmcgarvey

3. Jun 20, 2004

### 1+1=1

these negative bases are quite interesting, although are they reallly used all that much? i know that everyone i've talked to is basically saying "no." however, almost anyone could make up their own number system, but no one else could understand it.

4. Jun 20, 2004

### Gokul43201

Staff Emeritus
In Alice in Wonderland, when Alice has fallen down the rabbit hole, she wonders if she's swapped places with someone called Mabel. To discover her true identity, she recites the 4 times table:

"But if I'm not the same, the next question is, 'Who in the world am I?' Ah, that's the great puzzle!... and I'm sure I can't be Mabel, for I know all sorts of things, and she, oh! she knows such a very little!... I'll try all the things I used to know. Let me see: four times five is twelve, and four times six is thirteen, and four times seven is -- oh dear! I shall never get to twenty at that rate!"

Figure out why this is true !

5. Jun 20, 2004

### 1+1=1

this definitely has something to do with numbers that are NOT base 10. other than that, i'll have to sleep on it.

6. Jun 20, 2004