Puzzle log

Daily (ish) puzzles worth scribbling on a napkin.

Some math, code, logic, whatever puzzles/problems I found enjoyable. A puzzle a day keeps the dementia away or so they say .

Featured prompt

Cube Plus One Prime

Standard

There is a prime number p such that 16p + 1 is the cube of a positive integer. Find p.

ProofNumber TheoryAIME

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Nov 17, 2025

Cube Plus One Prime

Standard

There is a prime number p such that 16p + 1 is the cube of a positive integer. Find p.

ProofNumber TheoryAIME

Nov 16, 2025

Anh Reading Problem

Warmup

Anh read a book. On the first day she read n pages in t minutes, where n and t are positive integers. On the second day Anh read n+1 pages in t+1 minutes. Each day thereafter Anh read one more page than she read on the previous day, and it took her one more minute than on the previous day until she completely read the 374 page book. It took her a total of 319 minutes to read the book. Find n + t.

ProofAIME

Nov 13, 2025

Weighted Dice Problem

Warmup

Two dice appear to be standard dice with faces numbered 1 to 6, but each die is weighted so that the probability of rolling the number k is directly proportional to k. The probability of rolling a 7 with this pair of dice is m / n where m and n are relatively prime positive integers. Find m+n.

ProofProbabilityAIME

Nov 12, 2025

Coffee Conundrum

Warmup

You have a cup of coffee and a cup of milk with equal volumes. You scoop one spoon of coffee into the milk, stir, and then scoop a spoon of the mixture back into the coffee. Which cup ends up with more of the other liquid?

Logic

Nov 12, 2025

Paper Fold Proof

Warmup

Show that no matter how many times you fold a rectangular piece of paper (only perfectly in half each time), the ratio of its sides always remains rational.

ProofGeometry