x Turn on thread page Beta
 You are Here: Home >< Maths

# The Maths Problem You Will Never Solve (Probably)! watch

1. (Original post by Simplicity)
Sorry, but modular arithmetic is not a clock. The clock analogy is at best weak. Also, lol modular is not a hard word, so why even mention clock. Sorry, but lol I read through a book called music of the primes and yeah had to read clock arithmetic and quantum drum a thousand times.
Because it is sometimes called clock arithmetic, and gives the person I was responding to something else to google that might potentially yield more accessible results. I don't care what book you had to read or how much the term annoys you, it is a term that is used. I didn't say it was one I particularly liked.
2. (Original post by generalebriety)
Because it is sometimes called clock arithmetic, and gives the person I was responding to something else to google that might potentially yield more accessible results. I don't care what book you had to read or how much the term annoys you, it is a term that is used. I didn't say it was one I particularly liked.
Lol, I have never read a real maths book that used clock arithmetic. But, lol hmm modular arithmetic is not that hard to understand. I don't know but in a way talking about clocks is like sort of talking down to someone like they are a idiot(it would be like talking to someone about fractions and then talking about cutting cakes). Its if you can understand division then you can understand modular arithmetic, as its just the remainder after divison(I hope to god that yr 10s can understand division).

P.S. Also, a clock is misleading, as I don't see what division has to do with clock. The only clock thing about it is that if you have say x mod m, then you can add and subtract m and they will still be equivalent mod m. But, lol mod is not a clock
3. (Original post by Simplicity)
Lol, I have never read a real maths book that used clock arithmetic. But, lol hmm modular arithmetic is not that hard to understand. I don't know but in a way talking about clocks is like sort of talking down to someone like they are a idiot(it would be like talking to someone about fractions and then talking about cutting cakes). Its if you can understand division then you can understand modular arithmetic, as its just the remainder after divison(I hope to god that yr 10s can understand division).

P.S. Also, a clock is misleading, as I don't see what division has to do with clock. The only clock thing about it is that if you have say x mod m, then you can add and subtract m and they will still be equivalent mod m. But, lol mod is not a clock
Oh, do shut up.
4. (Original post by generalebriety)
Yep. Actually, from what you've done, it doesn't take long to prove the converse. (Any number m that isn't divisible by 3 is either 3n+1 or 3n-1 for some n - check a few cases and notice that, if 3n has digit sum a multiple of 3, then 3n+1 or 3n-1 will not have digit sum a multiple of 3. Fiddly, but not "hard".)

The GCSE/A-level syllabus won't teach you it, I'm afraid. It's a very interesting (and very accessible) part of number theory - you might want to look into it at some point if you're interested. Here's a couple of links, the first rather simplistic and the second rather advanced, that eventually lead up to solving this problem using modular ("clock") arithmetic: [1], [2] - and of course, although it might take you an hour or two to get your head round this solution, you should see it from the point of view of someone who already knows a bit about modular arithmetic. Once you're armed with modular arithmetic, the problem becomes really easy - in fact, I solved it myself in half a line earlier in this thread.

No problem.
Oh, thank you for the link, i really appreciate it!! I think you've encouraged me to expand my horizon as a mathematician!! Thanks!! hey, this may be a bit cheeky and audacious but may i ask a favour? D'ya know any other topics you recommend studying? what books do you recommend for me to learn these sort of things? list plz? i'd really like stuff that will take me from beginer to deep insight.
I'd really appreciate for stuff like number theory, geometry, algebra, etc.... thnx!!! anything problem solving type will b awesome

TSR Support Team

We have a brilliant team of more than 60 Support Team members looking after discussions on The Student Room, helping to make it a fun, safe and useful place to hang out.

This forum is supported by:
Updated: February 14, 2010
Today on TSR

### Happy St Patrick's day!

How are you celebrating?

### Stay at sixth form or go to college?

Discussions on TSR

• Latest
Poll
Useful resources

### Maths Forum posting guidelines

Not sure where to post? Read the updated guidelines here

### How to use LaTex

Writing equations the easy way

### Study habits of A* students

Top tips from students who have already aced their exams

## Groups associated with this forum:

View associated groups
Discussions on TSR

• Latest

The Student Room, Get Revising and Marked by Teachers are trading names of The Student Room Group Ltd.

Register Number: 04666380 (England and Wales), VAT No. 806 8067 22 Registered Office: International House, Queens Road, Brighton, BN1 3XE