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
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
Crosswords are among the worlds most printed and devised puzzles. And though they are puzzles with words, they are not language puzzles and they can be fairly easily generated once you have a large dictionary in electronic form available.
But Crosswords are so common place I have thus far avoided them in this blog. There are several number variants however, and the one presented here is geared towards math buffs.
| Horizontal | Vertical |
| 1 square with identical first and third digit 3 fibonacci number 5 perfect number 7 number of cards in bridge 9 happy number 10 catalan number 11 monodigit number 12 lucas number 14 happy number 16 narcistic number 18 circular prime 19 fibonacci number |
1 factorial number 2 prime number 3 fourth power 4 catalan number 6 multiple of 11 8 third power 9 perfect number 12 third power and a square 13 fibonnacci number 15 triangular number 16 fermat prime 17 square |
You can check your solution here
At the optician, I saw several spectacles for sale. The prices of the frames, still without the glasses, showed a very clear pattern.
What is the price of the one labelled with the question marks?
Usually you can find a new braintease here usually on Friday. Solutions are generally provided one week later.
You can check your solution here
Here is another age problem:
On a question about her age, Alice replied:
Me, I’m very old. I’m even older than my sis Barbara and I were together 7 years ago. And though Barbara is just two years younger than I am, she is still very young: she even isnt as old as we were together seven years ago!
What is the age of the girls?
You can check your solution here
There are numerous puzzles about ages, and most of them can be solved with elementary algebra, though the hassle of tracking forward and backward into time can sometimes be confusing.
2) My friend and his granddaughter*
A friend told me: 3 years ago, I was thrice as old as my granddaughter. 8 years before I that, that is, 8 years before I was three times as old, I was four times as old.
How old is my friend?
You can check your solution here
Four combinations of a square and a circle have been labelled with a three letter code. What code should the combination in the middle have?
You can check your solution here
The Polish mathematician Stefan de Banach could have said: In the year x I was x^2 years old.
What is the next year in which a person can be born and later make this claim?
You can check your solution here
There are 5 filled and five empty glasses in a row:
A) Can you move 4 glasses in such a way that full and empty glasses alternate?
B) Can you move just 2 glasses so that full and empty glasses alternate?
I invite you to comment on the puzzle, but please do not give the solution. The solution will be given later.
You can check your solution here
1) Drink**
This weeks puzzle is a cryptarithm, one of the type of a non unique list:
BEER BEER BEER WINE WINE WINE WATER WATER WATER -----+ DRINK
Solve this with A less then B.
It goes without saying that I strongly advice you not to drink any beer or wine when solving this puzzle. And while we’re on the topic: though a glass of wine is reported to be healthy, be aware that any large amount of alcohol destroys a number of braincells, and that brains which are not full grown may suffer more damage from alcohol than full grown brains.
(Solution: 60)
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