The 52-Card Challenge : mathriddles

november 2019 by mcherm

A challenging, surprising, and interesting math puzzle. A variant of the 100 prisoner problem.

math
puzzles
via:reddit
november 2019 by mcherm

the Infinity Puzzle: a new kind of jigsaw puzzle | Nervous System blog

may 2018 by mcherm

It's equivalent to a Klein bottle.

personal_net
via:HackerNews
puzzles
math
topology
may 2018 by mcherm

A more interesting algebra puzzle than typical. - math

september 2017 by mcherm

A good algebra problem for kids. "How many cats are n the box?"

math
puzzles
via:reddit
september 2017 by mcherm

What's your favorite math puzzle? : math

may 2016 by mcherm

Several interesting ones.

puzzles
math
via:reddit
may 2016 by mcherm

Advent of Code

may 2016 by mcherm

A programming challenge puzzle (well, 50 puzzles) that looks pretty interesting.

programming
puzzles
via:NedBatchelder
may 2016 by mcherm

Answer to a 150-Year-Old Math Conundrum Brings More Mystery | WIRED

june 2015 by mcherm

An interesting tale about a proof of a math problem simple enough to explain. And it also comes with an interesting set of puzzles ranging from moderate to difficult.

math
wired
puzzles
via:reddit
june 2015 by mcherm

Will you play the "Red and Black" card game? - Boing Boing

february 2015 by mcherm

A very simple math puzzle, but suitable for doing with children.

math
puzzles
february 2015 by mcherm

Impossible Escape?

february 2015 by mcherm

64 randomly or maliciously flipped coins placed on a chessboard. Opponent selects a square. You must convey which one to a confederate by flipping just one coin over.

math
puzzles
mathpuzzle
via:reddit
february 2015 by mcherm

A Rubik's cube solution that is easy to memorize

december 2014 by mcherm

A very well-done page to easily memorize a formula for beating the Rubik's cube.

puzzles
rubikscube
via:CedricBeust
december 2014 by mcherm

Is there a number that follows 2x = reverse digits of x : math

august 2013 by mcherm

In some bases there are numbers such that 2x is x with the digits reversed. Which bases?

math
via:reddit
puzzles
august 2013 by mcherm

CSE Blog - quant, math, computer science puzzles: Puzzle: What's the number on my Hat?

july 2013 by mcherm

Another interesting hat puzzle.

math
puzzles
via:HackerNews
july 2013 by mcherm

Delightful Puzzles

july 2013 by mcherm

Some REALLY GOOD math puzzles.

via:HackerNews
puzzles
math
todo
july 2013 by mcherm

Coin Puzzle: Predict the Other's Coin | Hacker News

december 2012 by mcherm

Two people predicting the other's coin flips moire often than you'd expect.

math
probability
puzzles
via:HackerNews
december 2012 by mcherm

Brainteaser driving me crazy!! No solution found on internet. Please look at! : math

december 2012 by mcherm

An excellent brainteaser.

math
via:reddit
puzzles
december 2012 by mcherm

Zeckendorf’s Theorem & Simple Code Implementation | Swageroo Algorithms

october 2012 by mcherm

A good math puzzle: all positive integers are uniquely the sum of non-consecutive Fibonacci integers.

math
puzzles
via:reddit
october 2012 by mcherm

Puzzles.COM - Logic Puzzles - All GridWorks

january 2012 by mcherm

Some logic puzzles. Starts really easy (6-yr-old level) and goes to fairly challenging.

math
puzzles
logic
january 2012 by mcherm

Blue Eyes - A Logic Puzzle

september 2011 by mcherm

Leave the island if you learn your eye color.

RandallMunroe
math
puzzles
via:reddit
september 2011 by mcherm

XWord Info -- Puzzles with Multiple Answers

july 2011 by mcherm

Crossword puzzles with more than one answer.

puzzles
personal_net
via:HackerNews
july 2011 by mcherm

My friend and I came up with some variations on a classical puzzle. : math

june 2011 by mcherm

I solved the basic, and the 1st variation so far.

math
puzzles
via:reddit
june 2011 by mcherm

r/rpg, help me test my puzzle : rpg

april 2010 by mcherm

Some logic puzzles -- I posted a few.

mypostings
logic
puzzles
via:reddit
gaming
april 2010 by mcherm

Algorithm X in 30 lines!

march 2010 by mcherm

A sudoku solver in about 30 lines of code.

puzzles
sudoku
python
programming
via:reddit
personal_net
march 2010 by mcherm

Still More JavaTM Puzzlers

september 2009 by mcherm

8 REALLY HARD really simple java code puzzles.

java
programming
puzzles
fun
via:BillTheLizard
september 2009 by mcherm

A Programming Interview Question, Explored

september 2008 by mcherm

A knight, a dragon, and 6 poisoned wells.

math
puzzles
september 2008 by mcherm

Index of Bongard Problems

january 2008 by mcherm

A large collection of "Bongard problems" (determine-the-rule problems based on simple drawings).

puzzles
fun
game
logic
math
january 2008 by mcherm

Why Mathematicians Now Care About Their Hat Color

may 2007 by mcherm

Hat color puzzle.

math
gametheory
puzzles
may 2007 by mcherm

The "Eternity Puzzle"

may 2006 by mcherm

VERY difficult jigsaw puzzle solved (over a period of years) by mathematicians. Article details the techniques used, which are interesting.

math
puzzles
personal_net
games
may 2006 by mcherm

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