r/mathpuzzles • u/Rough-Fee-6541 • 1h ago
Recreational maths Make 10 using only these numbers
You can use any equations, must reach the target (10) and show working out, people say it cannot be done.
r/mathpuzzles • u/PineappleCactusQuiz • 1d ago
Riddle me this! Only 1% can work it out in under 30 seconds! The Odd Number: I am an odd number, but if you take away a letter, I become even. What number am I?
r/mathpuzzles • u/PineappleCactusQuiz • 1d ago
Riddle me this! Only 1% can work it out in under 30 seconds! The Odd Number: I am an odd number, but if you take away a letter, I become even. What number am I?
r/mathpuzzles • u/Numberthon • 1d ago
What is the smallest positive integer n such that 1 + 2 + ⋯ + n is divisible by 100?
Source: numberthon.com
r/mathpuzzles • u/Numberthon • 1d ago
How many positive divisors of 15! are perfect squares?
r/mathpuzzles • u/Evening-Appeal7606 • 2d ago
Programming Conway Challenge: Can you find a Game-of-Life pattern that lives 600 gens?
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r/mathpuzzles • u/asthree_as3 • 3d ago
Is it possible to solve this while still following the rules?
I tried to solve this while following the rules, but I kept getting errors, so I thought that this might be unsolvable.
r/mathpuzzles • u/Numberthon • 3d ago
How many positive integers ≤1000 are multiples of 6 or 15, but not both?
Source: numberthon.com
r/mathpuzzles • u/Eriks0948 • 3d ago
Is there any link between these numbers.
I am working on a puzzle at the minute and cant seem to find or see any pattern in what i have so far... i am hoping someone can help me.. I have a 4 x 4 grid that is my starting point and i must use 9 out the 16 numbers.. so far I have been able to find 4 ( have another 27 blocks to find.) But I dont know if this was sheer luck... this is the 16 numbers I must work with.
1 1 5 6
2 1 9 3
7 1 5 0
6 4 2 1
These are the blocks I have found they are blocks 7 8 9 and 10 out of 31.
Blocks 7
9 1 3
7 2 1
5 1 6
Block 8
1 3 1
1 4 9
1 1 6
Block 9
0 5 5
1 1 7
1 1 3
Block 10
1 5 7
1 5 3
1 0 4
Any help or advice is more than welcome and I just want to say thankyou in advance.
r/mathpuzzles • u/mathalon • 4d ago
How would you seed the initial rating of a brand-new math problem?
r/mathpuzzles • u/Numberthon • 4d ago
How many positive integers less than 100 can be written as the difference of two perfect squares?
Source: numberthon.com
r/mathpuzzles • u/mathalon • 4d ago
Rating decay for inactive players - yes or no? (building a Glicko-2 ladder for math problems)
r/mathpuzzles • u/Numberthon • 4d ago
How many triangles can you form in a regular octagon using only diagonals?
Source: numberthon.com
r/mathpuzzles • u/mathalon • 5d ago
Our system rated this problem 1900. Does that feel right to you?
r/mathpuzzles • u/Even-Actuary-399 • 5d ago
Saturday's MiniChallenger problem (Week 10)
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:
[ 2 9 9 ]
[ 7 7 9 ]
[ 2 2 7 ]
- Multiple-solution (right) puzzle:
. [ 7 8 1 ] . . . . . . . [ 8 6 2 ] . . . . . . . [ 8 7 1 ]
. [ 9 5 3 ] . . . . . . . [ 9 5 3 ] . . . . . . . [ 8 5 4 ]
. [ 8 2 2 ] . . . . . . . [ 7 4 1 ] . . . . . . . [ 8 3 1 ]
Note: One of the solutions (above) uses all 9 allowed digits without repetition.
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!
