Good Math Riddles: Find Fun Challenges Here

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The discussion centers around finding good math riddles and explores a specific cake-sharing problem. A suggested method for ensuring fair division among multiple people involves a sequence of cutting and choosing, where each person has the opportunity to subdivide a piece before it is passed on. This method aims to ensure that everyone feels they have received a fair share, assuming they all desire the largest portion possible. However, one participant argues that the initial two-person cake-sharing method—where one cuts and the other chooses—does not guarantee fairness, as the chooser may select the smaller piece if they believe it to be advantageous. Overall, the conversation highlights the complexity of fair division in mathematical riddles and the nuances of perceived fairness in sharing.
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Does anyone know a site where I can find good math riddles?
Thanks.
 
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daniel_i_l said:
Does anyone know a site where I can find good math riddles?
Thanks.
Google math riddles, and you'll get a bunch. I only looked at one though and it wasn't good.
 
Here's one:

There is a simple procedure that ensure two people share in equal part a cake: one person cuts the cake, and the second chooses his/her piece first. What procedure should be taken for an arbitrary number of persons?
 
the cutter always gets the last piece?
 
Werg22 said:
There is a simple procedure that ensure two people share in equal part a cake: one person cuts the cake, and the second chooses his/her piece first. What procedure should be taken for an arbitrary number of persons?

This question is incorrectly stated, but I think I understand what you're asking. It won't ensure that people get an *equal* share-- it ensures that neither person is justified in thinking that they got an unfairly small amount of cake, assuming that each finds larger portions desirable.

But anyway, a solution to the arbitrary number of people would be:

A) Nth person cuts a piece from "the cake".
B) The piece is passed to the next person, who may further subdivide the piece if he/she wishes.
C) If the piece is subdivided further, excess is returned to "the cake"
D) Repeat steps B & C until each person (apart from the Nth) who does not already have a piece of cake has had the option to subdivide the piece.
E) Whoever was the last person to cut or subdivide the piece is given that piece.
F) Repeat steps A-E until only 1 person does not have a piece of cake, who is given the remainder of the cake.

This ensures that assuming everyone wants as large a piece as possible, that everyone has a portion that they must think (or must have thought) was fair, and is therefore unjustified in thinking is anything but fair.
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DaveE
 
Werg22 said:
There is a simple procedure that ensure two people share in equal part a cake: one person cuts the cake, and the second chooses his/her piece first.
It doesn't work. If I cut some tasty morsel in two to share with my wife, if one piece is larger than the other, I give her the larger piece. If I give her a choice she will invariably choose the smaller.
 
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