This is another clock puzzle from the 1978 Eureka magazine.
“The hands on my alarm clock are indistinguishable, and there are no numbers around the outside. Accidentally woken up by it one morning, I observed with a snarl that the hands were both pointing at minute divisions, and that they were 9 minutes apart.
Had it not been for my hangover, what could I have deduced?”
See the Hangover Clock Reading for a solution.
This problem from A+Click follows a classic pattern.
“There are 190 coconuts in a basket. Sailors one after another take out half of them and one each time until one is left. How many sailors are there?
Answer Choices: 5 6 7 8”
See Sailors and Coconuts for solutions.
This is a math Olympiad problem from Puzzle Sphere where Muhammad Zain Sarwar claims it is at Harvard entrance exam level.
“Given the functional relationship f(x + y) = f(x) + f(y) + xy with the known value f(4) = 10, determine the value of f(2023).”
Just try some examples and detect the pattern that defines the function.
See the Functional Equation Puzzle for a solution.
Here are two algebra problems from the 2025 Math Calendar.
“#1. Find the value of the ratio
#2. Find the value of the sum
z90 + z87 + … + z3 + 1
where z2 + z + 1 = 0.”
Remember the answers are days on the calendar.
See Two Algebra Puzzles for solutions.
These code-breaking puzzles are from MathsJam Shout for October 2025. The second one is reminiscent of the mesmerizing 1970s game Mastermind, which consumed many hours of my time.
See Two Codebreaking Puzzles for solutions.
This is another problem from Dan Griller.
“In the triangle ABC, CN and MB are straight lines, ÐCAB = 90° and CM = MA = AN = NB = 5. Find the exact area of the shaded region.”
See the Triangle Bow-tie Problem for a solution.
This is an earlier puzzle from Presh Talwalkar.
“A square pyramid has base PQRS and vertex O. Each edge has length equal to 20. Calculate the shortest distance along the outer surface of the pyramid from P to T, the midpoint of OR.”
See Shortest Pyramid Path for solutions.
This is another typical travel puzzle from the 2024 Math Calendar.
“A boat travels downriver at 30 mph, then goes back up along the same path at 20 mph. What is the boat’s average speed?”
As before, recall that all the answers are integer days of the month.
See Another Boat Puzzle for a solution.
This is a simple 1917 puzzle from Henry Dudeney.
“During a visit to the seaside Tommy and Evangeline insisted on having a donkey race over the mile course on the sands. Mr. Dobson and some of his friends whom he had met on the beach acted as judges, but, as the donkeys were familiar acquaintances and declined to part company the whole way, a dead heat was unavoidable. However, the judges, being stationed at different points on the course, which was marked off in quarter-miles, noted the following results:—The first three-quarters were run in six and three-quarter minutes, the first half-mile took the same time as the second half, and the third quarter was run in exactly the same time as the last quarter. From these results Mr. Dobson amused himself in discovering just how long it took those two donkeys to run the whole mile. Can you give the answer?
See Donkey Riding for solutions.
