What code corresponds with the figure in the centre?
You can check your solutions here
Tag Archives: Puzzles
Odometer
The display of the odometer in my car showed a number of five consecutive, decreasing digits. My mind wandered off. It was a nice number, of course. It was also clear what the next number with decreasing consecutive numbers would be, and how many kilometers I would have to drive. But what would be the next number that consisted of consecutive digits, and which also would be a prime number?
You can check your solutions here
Digital matchsticks (1)
Shikaku
Shikaku puzzles are puzzles which can be found in some magazines. They were invented by Nikoli, a Japanese puzzle firm. Allthough they can be drawn in black and white, the colored versions seem to be more popular. There are several websites offering them – see below They are also known as Shikaku ni Kire, rectangles, Divide by Squares and Divide by Box.
The basic is a square or rectangle which has been subdivided into rectangles. The border lines are not shown in the exercise – this is what the solver has to find out. The sizes of the rectangles are given as clues.
Example:
The solution:
As you can see in the examples above:
(1) Only rectangles are used;
(2) Every rectangle has exactly 1 square indicating its size;
Here are some puzzles with them:
1) Problem 6×6
2) problem 7×7
3) problem 12×12
There are several apps for your android smartphone or ipad around. Sites which offer shikaku puzzles are:
Sojuko
A Sojuko can be considered as part of the Sudoku family in the sense that the 3×3 square contains each of the digits 1 to 9 exactly once. Some of the digits have been omitted, and the puzzle is to restore the missing digits. As clues four circles are given, holding the sum of the numbers in the squares around them. The solutipon techniques however are reminiscent of Kakuro.
Sojuko number 1
Sojuko number 2
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I found them in “Terdege”, a puzzle add-on of the newspaper “Reformatorisch dagblad”.
61 equals 28?
Make the equation in the picture above correct. To do so, you may freely move the digits around. You may not add other stuff such as plus signs, multiplication signs, and so on.
Recently I purchased “Logic Brain Teasers”, published by Mensa. There was a puzzle on the back cover and while attempting to solve it as a family during dinner, the idea for this puzzle was born.
You can check your solution here
You are welcome to remark on the puzzle: its wording, style, level of difficulty. I love to read your solution times. Please do not spoil the fun for others by listing the solution.
I do offer my apologies that the puzzle above does not carry a christmas theme, as I had intended. I had two puzzles in mind, but in one I made an error in my calculation and for the other I had insufficient infomation on its origin.
Christmas time is something special in many parts of the world. For some, these are happy days with the family. For others, it’s just a few days off. For me, as an orthodox christian, it is a time of celebration.
Celebration, because where we humans develop irritation, dislike and even hate, God has come to offer a possibility of peace.
Celebration, becuase where we suffer poverty, He has come to share his richness with us.
Celebration, because where we suffer bondage, He has come to set us free.
Celebration, because the God, who is greater than our imagination can comprehend, chose to be born as a small and vulnerable baby.
I wish that you may enjoy the Christmas days and may experience a little bit of the peace, freedom, and richness he wishes to give us.
Knights on a chessboard
In chess a knight may move 2 up/down and one sideways, or 2 sideways followed by one up/down. See the following illustration:
How many knights can you put on a normal 8×8 chessboard so that no knight may take another knight? And can you show that that is the maximum?
This problem was posted at the Dutch mathematics olympiad 1996.
You can check your solution here
Pattern code – arrows
Here are some arrows, all different, and all labelled.
What should be the label of the arrow in the center?
You can check your solution here
A square
What is the smallest number of which the square ends with three identical digits? And indeed, 0 is excluded as a solution.
This is a slightly simplified version of a problem published as perplexity 466 by Henry Dudeney in The Strand magazine august 1919.
You can check your solution here
Rabbits and carrots
Here is a classic:
If 5 rabbits can eat 5 carrots in 5 minutes, how many carrots are eaten by half as many rabbits in half the time?
This kind of problem goes back to at least the middle ages. They have been formulated in many ways: slaves doing work, painters painting walls, cats catching mice, you name it.
You can check your solution here
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