A puzzle devised by the logician Raphael Robinson. Can you complete the following sentence: In this sentence, the number of occurrences of 0 is __, of 1 is __, of 2 is __, of 3 is __, of 4 is __, of 5 is __, of 6 is __, of 7 is __, of 8 is __ and of 9 …
There are certain mathematical and scientific problems that require guestimation, that is; educated guesses and estimates. These sorts of problems cover a wide range, from working out the number of coins or sweets in a jar, to working out the number of grains of sand held in a beach, to working out how many individual raindrops have fallen to the …
In an article regarding symmetry, my uncle proposed a puzzle: how could you make a calendar out of seven cubes, representing the date in the format: ddmmmyy. It involves using rotational symmetries to fit all the required letters and numbers onto the cubes to be able to show every day, month and year (with a limit on the year, as …