thnik again!

- Do you see this cable?
- That’s a very long cable if ever there was one!
- The cable has one thousand wires in it. I would like to know which wire at this end corresponds to which wire at the other end.
- Seems like a reasonable request.
- I have a battery and a light bulb to help me.
- No wonder I could not find them this morning!
- The bulb will lit up if I make a closed circuit with the wires.
- Can you connect the wires at each end?
- Yes, as much as I please.
- Let’s get to work then.
- Not so fast. I want to minimise the number of times I have to go from one end of the cable to the other.
- Can you see if the bulb is lit from the other end of the cable?
- Sure can.
- Are the wires coloured?
- Unfortunately no.
- I think I know the solution if there are two wires!
- There are one thousand wires.
- Just making conversation.

Problem source: wu:riddles.

When a piece gets difficult, make friends. – Vladimir Horowitz

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A word has been added or deleted, or replaced by another word, to arrive at the ‘almost a quote’ above. Which word?

- This is from a game I played las night against Celia.
- Who won?
- Can you find out what the last move was in the position in the diagram?
- Whose turn is it?
- That is a good question.
- Either Black moved the king or White moved the knight or the king.
- That’s a good start!

Problem source: Rund um das Schachbrett by Karl Fabel.

Patriotism is the willingness to kill and be killed for good reasons. – Bertrand Russell

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A word has been added or deleted, or replaced by another word, to arrive at the ‘almost a quote’ above. Which word?

The other day a friend of mine called. He said that he could not talk on the phone, but that we should meet face to face. We agreed to leave our respective houses immediately and head for the other’s house meeting somewhere along the way.

However, when we did ‘meet’ we didn’t notice it due to the thick fog. Later we found ut that we arrived at the other’s house respectively four and one minute after we ‘met’.

For how long did my friend be on his way? And what about me?

How good it is to sit down to write when you have not stood up to live. – Henry David Thoreau

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A word has been added or deleted, or replaced by another word, to arrive at the ‘almost a quote’ above. Which word?

In number theory, the totient  phi(n) of a positive integer n is defined to be the number of positive integers less than or equal to n that are coprime to n. For example, phi(9) = 6 since the six numbers 1, 2, 4, 5, 7 and 8 are coprime to 9. The function  phi so defined is the totient function. – Wikipedia

Here is problem 248 from Project Euler. As I write this only 90 people have solved it:

The first number n for which phi(n)=13! is 6227180929. Find the 100,000th such number.

If this is not your cup of tea go for the second such number and drink some coffee instead.

Wise men talk because they have something to say; women, because they have to say something. – Plato

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A word has been added or deleted, or replaced by another word, to arrive at the ‘almost a quote’ above. Which word?

Welcome to PhilSci Archive, an electronic archive for preprints in the philosophy of science. It is offered as a free service to the philosophy of science community. The goal of the Archive is to promote communication in the field by the rapid dissemination of new work. Authors who wish to post papers to the Archive should first consult the Archive Policy.

Publication has been undergoing a revolution thanks to the Internet. PhilSci Archive shows one way of getting published without having to wait for peer review and publication dates and only being available for those who can afford the high subscription posts. Even Educational Studies in Mathematics has changed with the times. Here is a free article called ‘Every unsuccessful problem solver is unsuccessful in his or her own way: affective and cognitive factors in proving.’

Can other follow suit? Is the software expensive?

This archive is running on eprints.org open archive software, a freely distributable archive system available from eprints.org.

Other institutions are invited (and encouraged) to set up their own open archives for author self-archiving, using the freely-distributable eprints.org software used at this site.

This site is running software from eprints.org / revision: EPrints 2.2.1 (pepper) [Born on 2002-11-14]

EPrints is free software developed by the Department of Electronics and Computer Science at the University of Southampton, England.

For more information see eprints.org

Find seven friends who love fractions and invite them to an intellectual tug of war here.

Scroll down the page to the Fraction and Ratio Games. It is the rightmost game.

After the game you get instant feedback.