# Dividing by 1 is impossible

1. Oct 21, 2007

### MrXow

Oddly enough I came across this on Uncyclopedia.
Can you really divide by 1?
I know that it can be mathematically done with ease, but physically can it be done?
Imagine a pie, and your dividing tool is your knife. If you want to divide the pie in 2 you can do that just cut the pie down the middle. If you want to divide it by 4 just cut it down the middle then do it again perpendicular to the original cut. But if you want to divide by 1 you end up not using your knife at all. You therefore don't divide the pie and do not divide by 1.

I hope this is the right forum.

2. Oct 21, 2007

### TMM

By your same logic, you can only divide by integers.

3. Oct 22, 2007

### Hurkyl

Staff Emeritus
I think this is merely a matter of language. Natural language has evolved to include an artificial distinction between "0" and "more than 0". (or more generally, between "less than 0", "0", "1", and "more than 1") While this is efficient for everyday communication, it has the unfortunate side-effect of constraining our thought -- we have a habit of excluding special cases when we really ought not to do so.

And another thing -- don't make a fallacy of equivocation. There are at least two distinct meanings for the word "divide" in your post: the English verb meaning a particular arithmetic calculation, and the English verb meaning to separate into parts. That they use the same word does not mean they are the same thing.

Last edited: Oct 22, 2007
4. Oct 22, 2007

### nesna

what do you get, when you want to divide a pie by 1? The entire pie itself.

what do you get when you want to divide a number by 1? The number itself.

5. Oct 22, 2007

### MrXow

Yes so you don't actually divide the pie or the number. If you want to say oh I wonder what 7/1 is. You already have the answer before you divide. And your not even dividing it up.

6. Oct 22, 2007

### LightbulbSun

You're confusing yourself. Of course dividing by 1 is possible. If it was impossible, you'd have no answer.

7. Oct 22, 2007

### MrXow

I mean its impossible because you don't actually do any dividing. The answer is already there and you do not divide it.

8. Oct 22, 2007

### MrXow

It's like a limit, sin(x)/x never gets to 0, but you know that it would be 1. You don't actually divide by 1 you just know that like 7/1.00000001 is roughly 7.

9. Oct 22, 2007

### LightbulbSun

So you're saying it's a tautology? That still doesn't make dividing by 1 impossible.

10. Oct 22, 2007

### christianjb

It's not a totally trivial observation. It's interesting that there exist certain mathematical operations which are equivalent to doing nothing at all. Maybe the OP is going to grow up to be a group theorist!

11. Oct 24, 2007

### JonF

For those of you still debating this you need to read this again:

12. Oct 24, 2007

### sepowens

Dividing by one is basicly the 'do nothing' operation from group theory. It is the same as the 'add zero' operation under addition. The denominator tells how many pieces are left of the whole after you use the knife on the pie. So division by 2 is 'make one slice across the pie and leave 2 pieces', division by three is 'make 2 slices with the knife and leave three pieces,' etc. It is easy to see that on this incremental basis division by 1 is 'make no slices with the knife and leave one whole piece.' This would also go towards explaining why division by 0 is impossible as it is -1 slices with the knife and the command would be 'take away a slice that does not exist made by the knife and make the entire pie disappear (0 pieces).'

13. Oct 24, 2007

### MrXow

Ya the pie metaphor doesn't explain negative pie.

14. Oct 24, 2007

### arildno

Please not think your kindergarten maths has anything to do with the concept of division.

15. Oct 24, 2007

### MrXow

What's the OP?

16. Oct 24, 2007

### christianjb

Original poster

17. Oct 25, 2007

### out of whack

Is this topic over yet? If it is then I need someone to explain why I cannot add 0 to my pie...

18. Oct 27, 2007

### i like sleeping

Now all we need to do is learn how to physically divide the pie by a half, and never go hungry again :)

19. Oct 28, 2007

### JasonRox

That's you. :)

20. Oct 29, 2007

### d_leet

There are much better examples, especially since if x=pi then sin(x)/x is, in fact, equal to zero.