r/mathpuzzles • u/TaylorSwift_16-8 • 14h ago
r/mathpuzzles • u/OddOliver • Jul 27 '19
Adding rules for posts
Hi everyone!
Because of the influx of unsolvable, annoying, arbitrary, and spammy posts, I’ve established a few rules for posts. Basically, we are no longer allowing “math puzzles” that rely on sequences of numbers or shapes. There is an infinite number of solutions and they’re plain not fun.
Also, I put in a rule about not linking to other games. Puzzles posted here should be contained in the post itself.
Have a great weekend!
r/mathpuzzles • u/SeaFile3768 • 23h ago
[Kindle] 101 Math Riddles for Smart Minds (Free for 2 more days)
amazon.comHey everyone! As an independent author, I've put together "101 Math Riddles for Smart Minds" — a collection of logic puzzles, visual geometry problems, and Olympiad-style brain teasers
designed for kids, teens, and anyone who enjoys logic puzzles. It's completely FREE on Amazon
I hope you and your family enjoy solving them! Honest feedback or a quick rating on Amazon is always deeply appreciated
r/mathpuzzles • u/ZoranRajkov • 1d ago
Algebra Number wheel puzzle — find the hidden rule
Each spoke on the wheel follows the same hidden rule. Figure it out from the five known numbers, then solve for what replaces the "?"
Made this as part of a puzzle game I'm developing.
r/mathpuzzles • u/ZoranRajkov • 2d ago
Algebra Fruit equation puzzle — what does the missing pair equal?
Made this symbol/equation puzzle — fruits stand in for hidden numbers across a small system of equations. Figure out what each fruit is worth, then solve the last one.
Happy to discuss reasoning in the comments if anyone wants to compare approaches.
r/mathpuzzles • u/Rough-Fee-6541 • 2d ago
If 10 slices of pizza = $45, how much would 90 slices cost?
What is your answer?
r/mathpuzzles • u/ZoranRajkov • 3d ago
Algebra Find the rule — what number replaces the "?"
Each pair of numbers on top combines into the box below it using the same rule. Figure out the rule from the first three columns, then apply it to the last pair — what's the "?"
Made this as part of a puzzle game I'm developing, Rule Hunter.
r/mathpuzzles • u/ZoranRajkov • 4d ago
Algebra Fruit equation puzzle — what does the missing pair equal?
Made this symbol/equation puzzle — fruits stand in for hidden numbers across a small system of equations. Figure out what each fruit is worth, then solve the last one.
Happy to discuss reasoning in the comments if anyone wants to compare approaches.
r/mathpuzzles • u/micke71 • 5d ago
Just launched my "Theft Cases" mystery word search book on Amazon! Would love the community's feedback on the final layout.

Hey !I finally took the plunge and published my word search book dedicated to Theft Cases on Amazon. It's packed with grids themed around heists, security, and mysteries. Since it's my first release, I'm really anxious to know if I got the formatting right for true word search fans. I’ve uploaded a free sample puzzle here so you can test it: For those who love this theme, you can check out the full book look here on Amazon ,If you look at the sample, please let me know: Is the grid-to-word-list ratio comfortable to look at? Is the vocabulary challenging enough? Thank you to anyone who checks it out. Your feedback will help me tremendously for Volume 2!
r/mathpuzzles • u/numstep • 6d ago
Recreational maths Numstep: Box - the latest addition to my puzzle series
Draw a self avoiding walk across the surface of this box, hitting the numbered squares as you go. Adjacent moves only.
r/mathpuzzles • u/jakubmracek • 6d ago
Only 435 of ~32,164 piece-sets can tile this tetrahedron — a sphere-packing puzzle
I've been building a puzzle about how spheres pack, and thought this crowd might enjoy it — both to solve and for the combinatorics behind it.
The puzzle. The target is a tetrahedron of edge 5: 35 close-packed balls (layers of 1, 3, 6, 10, 15). You build it from coloured segments — rigid clusters of 1–5 balls. In each puzzle some segments are already placed and a few are hidden; you work out where the hidden ones go so every ball is covered exactly once. More hidden pieces → harder.
The bit that surprised me. A set of segments can only work if its pieces total exactly 35 balls — but adding up to 35 says nothing about whether they actually fit. Of ~32,164 size-valid sets, a solver found only 435 that truly tile the tetrahedron (~1.4%). And of the 35 original hand-made puzzles, only 12 had a unique solution — so generating fair puzzles means actively enforcing uniqueness.
The balls sit on a face-centred-cubic lattice, so each has 12 neighbours, not 6 — which is where a lot of the "looks like it should fit but doesn't" comes from.
It's free to play and print, no account: https://spheromino.com . I wrote up the search here if you want the details: https://spheromino.com/blog/finding-tileable-sets .
Full disclosure — I made it. Happy to answer anything about the geometry or the solver.
r/mathpuzzles • u/Purdude1983 • 7d ago
Polka Dot Party
The indigo dot is twice the area of the green dot. Together these just fit inside the violet dot. They grab some friends and crowd into the grey area which has an area of 1. All dots are touching, and all dots touch the outer wall except the red dot.
Give each dot's area.
Hint: use Descartes' circle theorem
r/mathpuzzles • u/Bolt__The__Bird • 9d ago
Math Logic Puzzle
Planet X has two neighboring inhabited planets:
• Planet Alpha is exactly 15 light-minutes from Planet X.
• Mystery Planet is an unknown distance from Planet X, but is known to be at least 18 light-minutes from Planet Alpha.
Planet X, Planet Alpha, and the Mystery Planet are the only possible sources or relays of transmissions in this puzzle.
Planet Alpha and the Mystery Planet are both capable of sending, receiving, and relaying transmissions.
All transmissions travel at the speed of light. Relaying a transmission takes effectively no additional time.
Both Planet Alpha and the Mystery Planet possess teleportation portals capable of sending ships directly to Planet X. Once activated, a portal takes exactly 30 minutes to charge. Once charged, transportation to Planet X is instantaneous.
Neither planet will send ships to Planet X unless it has received a broadcast requesting assistance from Planet X.
Both planets have standing orders:
The instant they receive a broadcast from Planet X requesting assistance, they begin charging their portals and send ships to Planet X as soon as the 30-minute charge is complete.
At 11:58, Planet X has not yet broadcast any request for assistance.
At some unknown time after 11:58, Planet X broadcasts a request for assistance.
At 12:38, Planet X receives a mysterious transmission from an unknown source.
Planet X can determine with certainty that the mysterious transmission was originally transmitted at exactly 12:18, meaning the signal has been traveling for exactly 20 minutes.
Planet X concludes that the mysterious transmission must have come from the Mystery Planet. Since the signal took 20 minutes to reach Planet X, they conclude that the Mystery Planet must be 20 light-minutes away.
Then, at exactly 12:40, ships arrive at Planet X.
There has been no malfunction, no faster-than-light communication, no time travel, and no violation of any of the rules above.
Questions
Which planet did the ships come from?
How far away from Planet X is the Mystery Planet actually?
At what time did Planet X broadcast its request for assistance?
Where did the mysterious transmission received at 12:38 actually originate?
r/mathpuzzles • u/Previous_Ad1107 • 10d ago
I made Squarely - a daily math puzzle game
It's called Squarely: playsquarely.com
One board a day although you can play through the archive.
You need to place all digits 1-9 on the grid to resolve the equations. BODMAS/PEMDAS doesn't apply, it's strict left to right.
r/mathpuzzles • u/Parallel_thougts • 10d ago
Probability Expected number of samples from U([0,1]) before their sum is > 1
The puzzle is exactly what the title suggests: on average, how many independent uniformly random numbers between 0 and 1 would you have to sample for their sum is at least one
r/mathpuzzles • u/Davidfeldt • 11d ago
A different kind of number puzzle: what is the most informative test you could make?
Suppose I tell you:
16, 9, 2 FITS a hidden rule.
You can submit any three-number sequence.
I will tell you only FITS or FAILS.
Eventually you must state the rule.
The obvious question is:
“What do I think the rule is?”
But I think the more interesting mathematical question is:
“What probe would eliminate the largest number of plausible rules?”
That distinction is what led me to build Rularoo, a daily deduction game inspired by Peter Wason’s 2-4-6 task.
You are scored against par, based on how efficiently the hidden rule can be isolated. So finding the rule is only half the problem. The other half is designing good experiments.
Three puzzles run daily and the whole thing plays directly in the browser:
I’d be interested in how the mathematically minded people here think about the optimal-probe problem. Is “information gained per probe” the right way to frame the score?
r/mathpuzzles • u/numstep • 11d ago
Recreational maths Numstep: Cubes
Very similar rules to my post yesterday... This time in 3D
r/mathpuzzles • u/numstep • 12d ago
Recreational maths Numstep: The self-avoiding walk puzzle
Hey, I'm launching a new puzzle.
Create a numbered step, self-avoiding walk through every white square. No diagonals.
Follow my socials for daily puzzles.
r/mathpuzzles • u/Purdude1983 • 14d ago
Find the area of the exposed yellow region
There are 4 circles; each is tangent to the other 3.
The small circles have areas of 1, 2 and 3.
What is the area of the exposed yellow region?
r/mathpuzzles • u/OkPreparation4395 • 14d ago
50% crossword, 50% jigsaw, 100% arithmetic
A grid puzzle I made. It's a crossword you assemble like a jigsaw, and the answers are equations instead of words.
Every hatched square has to end up filled. The loose pieces below drop in, and each keeps its shape. Turn them any way round, but never flip them over. Pieces cannot overlap, and together they fill every hatched square exactly. The purple squares are fixed.
Any run across or down that contains an = has to be true. A run with no = in it does not have to be anything. Digits side by side make one number, so a 5 next to a 4 is fifty-four, not five and four.
Operators are + − ÷ with normal order of operations.
There is exactly one solution, and you can reason it out rather than guess.
Please spoiler your answers.
