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
Today I proudly present our first free e-book!
This e-book contains 30 unique number puzzles. The puzzles range from brainteasers to futoshiki puzzles and matchsticks problems. Some puzzle types have been published on this blog, others are new.
You can download this e-book here
justpuzzles 