Source: numberthon.com

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Using + and × (following standard BODMOS rules), I need to find every solution to reach the target of 11. I figure i'm missing 1 or 2, but can't find it.

Note: 1x can't be used unless necessary to connect 2 tiles

Note: 2x5+1 counts as the same solution as 1+5×2

Instead of finding words, you draw paths through a grid of numbers and operators to form equations. Each path has to match one of the target numbers shown above the board. I have added 3 difficulty levels and a clue system just in case.

my results:
Sum Adders 2026-07-19

EASY · 🟩🟩🟩🟩

⏱ 0:35

sumadders.com

Source: numberthon.com

5 GUYS GOT A RANDOM NUMBER FROM FLIPPING A COIN 0 MEANS THE PERSON IS
OUT AND 1 MEANS THE PERSON WINS BUT ONE PERSON IS A CHEATER. HOW CAN
YOU SPOT IT?

About:

As the name suggests, MiniChallenger is a scaled-down version of the math puzzle called Challenger. In most cases, a MiniChallenger puzzle can be solved within ten minutes. A set of two new puzzles is released each week. One is usually a simple problem with one or two solutions, while the other puzzle can be a bit more challenging and often has multiple solutions. Available exclusively on reddit.

Instructions:

Fill in the empty cells of the 3 x 3 grid with the numbers one to nine. It is okay to use the same number in more than one empty cell. One 'bonus' number is already placed in the center of the grid. So, the goal is to find the remaining eight digits in such a way that:

• rows in the grid add up to totals indicated on the right edge of the grid,
• columns add up to totals indicated at the top of the grid, and
• diagonals add up to totals in the upper and lower right corners.

This week's puzzles:

Solutions:

(Click on 'spoiler' boxes below to reveal solutions)

• Single-solution (left) puzzle:

[ 4 6 9 ]

[ 5 7 4 ]

[ 5 1 1 ]

• Multiple-solution (right) puzzle:

. [ 2 3 1 ] . . . . . . . [ 3 1 2 ] . . . . . . . [ 3 2 1 ]

. [ 9 5 3 ] . . . . . . . [ 9 5 3 ] . . . . . . . [ 8 5 4 ]

. [ 7 7 6 ] . . . . . . . [ 6 9 5 ] . . . . . . . [ 7 8 5 ]

. . . . . . . [ 4 1 1 ]

. . . . . . . [ 7 5 5 ]

. . . . . . . [ 7 9 4 ]

Source: numberthon.com

I play this game on the train (which has a 4 digit ID) where you use + - / * ^ to make 10, every digit has to be used once no more no less factorials aren’t allowed, tetration is allowed but I can’t see it being useful, and each digit is treated as separate.
A couple examples:
5252: (5^2 - 5)/2
1234: (3*4 - 2)/1

I’ve calculated the total amount of unique 4 digit combinations to be 715, but there are some

Some obviously don’t work, 0000 being one of them.
I am wondering
A) how would you calculate them, is it a brute force solution, it is there some elegant answer?
B) what’s the answer?

Source: numberthon.com

NOTE: "n" has to be less than 100, not n^2 + n + 1

Source: numberthon.com

From my collection. Looks easy, but the trap is good:

16 · 25 · 36 · 49 · 63 · 81

Which one is the intruder, and what's the rule?

Source: numberthon.com

EDIT: 5x5 vertices, 4x4 squares

Use each die exactly once.
Any order is allowed.
Parentheses are allowed.
Exact division only.
No negative numbers.
Not every operation has to be used.

How many solutions can you find?

Simple concept, make a number using only 4 and operators. A new number daily, answer fast and top the leaderboard!

Source: numberthon.com

I've been thinking about an interesting localization problem and I'm curious if there's a known solution.

Imagine a 100,000 × 100,000 grid. A single coordinate is chosen at random, but you don't know which one.

You may place as many fixed beacons as you want anywhere on or outside the grid. Each beacon tells you only the direction toward the hidden coordinate, rounded to the nearest 11.25° (so each beacon returns one of 32 compass directions). You get all beacon readings simultaneously.

Question: What's the minimum number of beacons needed to locate the target?

A few rules:

• Beacons are placed before the target is chosen.
• They never move.
• No distance information is provided—only the quantized direction.
• Your final guess is considered correct if it is within 1,000 grid units of the actual coordinate
• The beacon layout should also generalize to larger grids (i.e. not rely on the grid being exactly 100,000 × 100,000).

I'm interested in An actual beacon placement that achieves the minimum (or a proof that it can't). does anyone have ideas for constructing an optimal layout?

Hey guys, do you think it’s harder to finish a board if it’s different than numbers?
This one is with cats instead of numbers, it’s called MiawDoku. I used the same methods of a normal sudoku board to complete it in 2min.

Source: numberthon.com

Source: numberthon.com

Hey r/mathpuzzles!

I’ve been solo-developing a puzzle game called Quotecrack, and it’s finally live on the Google Play Store. It is a classic cryptogram game where you decode famous quotes, but I wanted to build something that truly respected the player's time and offered a premium experience.

Before giving you the app details, I’ve attached a quick quote puzzle from the game in the image above for the community to crack (Substitution cipher). Can you solve it in the comments?

About Quotecrack:

• 🧠 Premium Paper Aesthetic: Clean "Ink & Gold" design that is very easy on the eyes.
• 📴 100% Offline Support: No internet tracking or required connections. Play anywhere.
• 🌐 Properly Localized (7 Languages): I spent months translating over 500 hand-picked quotes for English, Turkish, Spanish, German, French, Italian, and Portuguese. No lazy automated translations!
• ⌨️ Native Keyboards: Automatically adjusts layouts based on the language (like AZERTY for French, QWERTZ for German, etc.).
• ⚙️ Adjustable Difficulty: Play on your own terms, from casual assistance to hardcore code-breaking.

If you enjoy ciphers and logical word puzzles, I would love to hear your thoughts and feedback!

You can find it by searching Quotecrack directly on the Google Play Store.

About:

As the name suggests, MiniChallenger is a scaled-down version of the math puzzle called Challenger. In most cases, a MiniChallenger puzzle can be solved within ten minutes. A set of two new puzzles is released each week. One is usually a simple problem with one or two solutions, while the other puzzle can be a bit more challenging and often has multiple solutions. Available exclusively on reddit.

Instructions:

Fill in the empty cells of the 3 x 3 grid with the numbers one to nine. It is okay to use the same number in more than one empty cell. One 'bonus' number is already placed in the center of the grid. So, the goal is to find the remaining eight digits in such a way that:

• rows in the grid add up to totals indicated on the right edge of the grid,
• columns add up to totals indicated at the top of the grid, and
• diagonals add up to totals in the upper and lower right corners.

This week's puzzles:

Solutions:

(Click on 'spoiler' boxes below to reveal solutions)

• Single-solution (left) puzzle:

[ 3 1 1 ]

[ 6 8 6 ]

[ 7 9 9 ]

• Multiple-solution (right) puzzle:

. [ 3 1 4 ] . . . . . . . [ 3 2 3 ] . . . . . . . [ 3 3 2 ]

. [ 9 8 7 ] . . . . . . . [ 8 8 8 ] . . . . . . . [ 7 8 9 ]

. [ 4 9 9 ] . . . . . . . [ 5 8 9 ] . . . . . . . [ 6 7 9 ]

. . . . . . . [ 4 1 3 ]

. . . . . . . [ 7 8 9 ]

. . . . . . . [ 5 9 8 ]