Martin Gardner has edited the book to make it as easy as possible for an English-reading public to understand, while carefully retaining nearly all the warmth and humor of the original. The book was originally published in Russia in 1956. They are almost always illustrated and often presented as amusing stories. The puzzles and brainteasers range from simple fun riddles to difficult problems, yet none requiring advanced math. Our whole family enjoys this book! It is divided into 14 chapters, each with different kinds of puzzles, such as matchstick puzzles, dominoes and dice, divisibility, cross sums and magic squares, "Measure Seven Times Before You Cut" (dissection puzzles), "With Algebra and without It" (tricky word problems), and so on. The Moscow Puzzles: 359 Mathematical Recreations The list above already has many links to websites with puzzles, but here are some more.Ĭhallenging puzzles sent to my puzzle contest. Where t is the thickness of the material and n the number of folds. The length of paper you would need for this folding would be many light years long.!!! It is given by the equation it is not physically possible to do this. However, the thickness of a piece of paper folded in half 50 times will be surprisingly big, more than 112 million kilometers! (The distance from the Earth to the Sun is about 150,000,000 km).īut. Those who do not know this problem usually assume that the stack will not be thicker than up to a couple of meters. You can easily reword it for example to have two flocks of birds in two trees.Ĭonverted to kilometers, we get that the thickness is (1/10) × 2 50 × (1/1000000) km = 112,589,991 km thick. Here is a puzzle that seems simple, but is a good critical thinking challenge for lower elementary school kids. Each "word" must add up to the number provided in the clue above it or to the left.ĭownload 5x5 Kakuro puzzles at KrazyDad. Kakuro puzzles are "cross-sum" puzzles-like mathematical crossword puzzles. Put the numbers from 1 to 9 in the circles so that the sum of the numbers on each side of a triangle is the same.Īt CoolMath4Kids you can view a hint and the solution. You can choose the size of the game, operations, and the difficulty level. Lower elementary children can use addition/subtraction and others can use multiplication/division or all four operations. So, Kenken is an excellent game to practice the four operations and logical thinking. The numbers you place in each box have to make the "clue" number using the given operation. In Kenken, you need to place the counting numbers in the squares just like in Sudoku, but additionally, you are given boxes with clues with math operations. How did he do this?Ĭlick here for the answer, but don't peek too early-give it a good honest try first! You can either play it yourself, or let the computer solve it.Ī gardener planted 10 trees in five rows.
If you've never played, try this online version. Tower of Hanoi is an old favorite puzzle where you move disks from one tower to another. See a hint and the solution at Cool Math 4 Kids site. Join all the dots using four straight lines and without lifting your pencil.Ĭlick here for the answer, but think about it first! This is one of my favorites! It is a simple puzzle, but illustrates beautifully the idea of "thinking outside the box." Move only three coins and turn the triangle upside down.Ĭlick here for the answer, but not before you've thought about it! How did he rearrange the pens so that there was only 1 pig per pen? He then found out he need 7 more wall pieces to finish his project. He needed some walls for another project so he rearranged the pins like this: You can see the solution and play an interactive version of this puzzle at (and many others too!).įarmer Black raises pigs and was raising them in modular pens, He currently Move three sticks and make the fish to swim in the opposite direction. The stars in the same row and column must have different colors. This is for you kindergarten folks-a coloring Sudoku game!
I also list several good puzzle websites and books at the bottom of this page. The challenging puzzles are on their own page. I have divide the puzzles into ones that are geometric in nature and ones that are math & logic puzzles. This collection is the result-a list of puzzles chosen by teachers and parents! Most only require the four basic operations or not even that, so they work well for elementary school children and on up. In February 2014, I asked my subscribers for their favorite math puzzle.
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