A Call For Riddles
Dear Reader,
You know that riddle about the wolf, the sheep, and the cabbage? You want to bring them across the river in a boat that can only carry one of them at a time, but you can’t leave the sheep and the cabbage alone together because the sheep will eat the cabbage, and you can’t leave the wolf and the sheep alone together because the wolf will eat the sheep.
Anyway, my 7-year-old son loves that riddle, and every night he demands a new riddle as good as that one, and to tell you the truth I don’t know many very good riddles. So today I thought I’d ask you kind readers for your riddles, to help me out with dinner time conversations.
Happy to take links! Maybe there’s a list or a book of great riddles somewhere I don’t know about!
Thanks!
Cathy
p.s. If you google “list of riddles” you come up with something that’s far too sophisticated and involves word play rather than logic. So maybe “riddle” isn’t the right word.
p.p.s. This list is pretty good. I found it by looking for “logic puzzles.”
mathbabe 
Though not helpful, your post reminded me of this retell one of that riddle:
http://bettermyths.com/the-goat-the-wolf-and-the-cabbage-or-poor-purchasing-decisions/
More to the point, your family might enjoy Smullyan’s books. I can vouch for What is the Name of this Book? and Alice’s Adventures in Puzzleland.
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I remember having this book as a youngster. Don’t know if it’s the right level for now.
☞ W.W. Rouse Ball and H.S.M. Coxeter • Mathematical Recreations And Essays
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Although this week’s column isn’t interesting, it frequently has math puzzles and riddles that might do the trick: https://www.theguardian.com/science/series/alex-bellos-monday-puzzle
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You know the one with 12 coins and a balance and you get three weighings to find the counterfeit?
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I came here to post this one – except I originally heard of it with seven coins with two weighings, on a balance scale. Maybe extend one problem with the other.
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How about game theory puzzles like the Prinsoner’s Dilemma? I found Monkey Puzzles with a few
http://monkeypuzzles.org/
And Wikipedia has a list of game theoretic games.
Steven Pinker includes games in a couple of his books. “Game people play” in _The stuff of thought_ has a game about when to bribe and how. It’s kind of an interactive game, so you could play it with two players if you’re willing to lose to a 7-year-old. Caveat: “when to lose to your opponent” game is risking your trust relationship forever.
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Also, if he likes riddles, would he also enjoy playing something like Tower of Hanoi? It was my first fascination with math as a child. Once you figure out the minimum number of moves for each quantity of pieces (this works best with more than just three pieces — the game is much more complicated and fun with many pieces and it helps to have more than three peices to corroborate the mathematical patternwhen you figure it out) then you realize that there’s a relationship between the number of pieces and the number of minimum moves which can be formulated in an equation.
https://www.mathsisfun.com/games/towerofhanoi.html
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https://fivethirtyeight.com/tag/the-riddler/
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This one has been vexing me for the past few days. It’s not difficult to arrive at the concensus answer because it felt similar to others, but I keep thinking that it seems difficult for the solution to be true, or to work out precisely why it is, so I keep having second thoughts. https://www.youtube.com/watch?time_continue=347&v=FSeXoq_DR3g
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You might try https://www.riddles.com , which seems to have a wide variety of riddles of many types.
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One more, or maybe two, from my own blog
https://languageandphilosophy.wordpress.com/2011/11/03/fun-with-godel/
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You might try http://puzzling.stackexchange.com/ with the logic-puzzle keyword.
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I loved riddles and puzzles at that age. Here are a couple from that time that I recall.
Q: What is better than presence of mind at an auto accident?
A: Absence of body.
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There is a snail at the bottom of a 30 foot well. Each day the snail climbs three feet up the well and each night it slides two feet down. How long does it take for the snail to get out of the well?
—-
My great uncle like this one:
Two ducks in front of two ducks, two ducks in back of two ducks, two ducks in between two ducks. How many ducks?
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One old classic I always enjoyed:
https://en.wikipedia.org/wiki/Missing_dollar_riddle
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There’s the census-taker problem (https://en.wikipedia.org/wiki/Ages_of_Three_Children_puzzle).
Similar to the fox, chicken, and cabbage problem, there’s the problem of crossing the bridge quickly enough (https://en.wikipedia.org/wiki/Bridge_and_torch_problem)
Raymond Smullyan has a lot of nice logic puzzles, many revolving around truth-tellers vs. liars. “What’s the name of this book?” Is pretty good, with lots and lots of logic puzzles.
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I also just came in to say Smullyan books.
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The book “What’s the name of this book” by Raymond Smullyan, a professional logician. I had a lot of fun with my girls using this on road trips.
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Anno’s Hat Tricks is one of my favorite kid’s books, and is about iterated theory-of-mind puzzles.
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What kind of hospital has patients that are not sick?
A maternity hospital.
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There’s a puzzle in one of the Die Hard movies https://www.youtube.com/watch?v=BVtQNK_ZUJg where you have a flowing fountain, a 5 gallon and a 3 gallon and need to get exactly 4 gallons. You might generalize the problem. How to get 1, 2, 4, 6, 7 etc.
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+1 for Smullyan, but also Martin Gardner. _Aha! Insight_ was a particular favorite of mine as a child that has problems that will be novel and challenging even for many adults presented in a light, engaging format that a young reader may appreciate. _Mathematical Games_ is a classic.
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Martin Gardner, particularly his book Aha!… Insight, was a favorite of mine as a kid. Aha! is particularly great for such a young reader because of it’s doodle-y, comic strip-like format. A search on Amazon says he has other books aimed at kids, too. _Mathematical Games_ and _Annotated Alice_ are classics.
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I wonder if the riddle about the common-knowledge problem (which you wrote up a couple years ago) would be over their heads currently, or fun?
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I quite like the swedish mathematician Paul Vaderlind for this kind of stuff. Apparently, he’s co-authored a book in english: http://www.amazon.com/Inquisitive-Problem-Solver-MAA-Book/
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oops; better post the full link: http://www.amazon.com/Inquisitive-Problem-Solver-MAA-Book/dp/0883858061/ref=la_B001KIW8WO_1_1?s=books&ie=UTF8&qid=1463067003&sr=1-1
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I think your son may really enjoy the book “Perplexing Puzzles and Tantalizing Teasers” by Martin Gardner.
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Occurs to me that even more than riddles, I like introducing youngsters to paradoxes. 2 books (of many) that cover a nice range/variety of paradoxes that youngsters can grasp are:
“Paradoxes In Mathematics” by Stanley Farlow
“The Big Think Book” by Peter Cave
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There are about 7 Ted Ed riddles –find using Google. My students love them. One is the bridge riddle mentioned above.
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I first saw the wolf/cabbage/sheep conundrum in The Moscow Puzzles: 359 Mathematical Recreations – first published in 1956 and still available https://www.amazon.ca/Moscow-Puzzles-359-Mathematical-Recreations/dp/0486270785/180-0224619-6619647?ie=UTF8&SubscriptionId=AKIAILSHYYTFIVPWUY6Q&camp=2025&creative=165953&creativeASIN=0486270785&linkCode=xm2&tag=duckduckgo-d-20
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Mark Palko has some puzzle videos on his YouTube channel “You Do The Math” and probably some non-video puzzles on his blog of the same name (linked from the YouTube page).
https://www.youtube.com/channel/UCuDBJHKjc95lf5Dc-OuLbjA
He notes George Polya and Henry Dudeney as great puzzle writers as well, neither of which I see above.
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Yep, Dudeney’s The Canterbury Puzzles is also good. My kids didn’t get into them as much as Smullyan’s logic puzzles, but tastes vary.
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