Questions tagged [number-property]

Question 1

puzzle from 2.191.149.204 — lv. easy Numbers are cool. If you join two (or more) numbers together, you get another valid number. For example add 3,756 and 4,192 together. You get 37,564,192 which is ...

Question 2

Inspiration from my usual column at the SPIEGEL. A mock binary $m$ is a decimal number with digits $0$ and $1$ only. Find the smallest $m$ such that $p\mid m$ for $p\leq30$ (it gets uninteresting fast)...

Question 3

Just had the idea but no solution and am too lazy to write a computer program (a solution without is preferred, of course). About 10^8 loops (10!*factoring) should suffice: c is a number consisting of ...

Question 4

Are there infinitely many perfect cubes, such as 216 and 512, which remain a positive cube after removing its first and last digits?

Question 5

You are given the following 4 by 4 grid of numbers. Create four groups of four numbers such that the numbers in each group share some common property. This puzzle is a (hopefully harder) sequel to ...

Question 6

Next puzzle You are given the following 4 by 4 grid of numbers. Create four groups of four numbers such that the numbers in each group share some common property. (The placement of numbers in the ...

Question 7

Is it possible to fill a 45 × 45 square with 1 to 2025 = 452 such that each pair of adjacent number is coprime? I'm pretty sure that it is possible and can probably get a construction, but I don't see ...

Question 8

I am considering to create a mathematical puzzle in the form of a numerical crossword. What I mean by that is a puzzle similar to a normal crossword but with digits instead of letters that form ...

Question 9

Each group in this connect-wall shares a number having those properties. Aliquot sum is a prime Catalan Digit sum is a cube Exponent of isolated Mersenne prime Fibonacci Friendly Hexagonal Lucas ...

Question 10

Question is as follows: 8619 - 4. 1253 - 0 9273 - 1 6656 - 3 1086 - ? What is the question mark? I tried summing the digits, checking number of 2's in prime factorization, but 2nd relation (1253 - 0) ...

Question 11

Take as a semi-related example a series of circles with radii 10, 9, 8, ..., 2, 1. Place the first (largest) circle in the center and subsequent circles around it, keeping tangency between subsequent ...

Question 12

Alice and Bob play the following game, taking turns. Alice starts and writes a digit from the set M={1, 2, 3, 4, 5, 6} at the blackboard. Bob appends another digit from the set M until a 2n-digit ...

Question 13

How do you get the numbers 33-99 by using the numbers 2,0,2,4

Question 14

All I need is 56-59, 69, 73, 75- 77, 79, 86, 90-94, 99. I've done the rest but I would love to hear other solutions. Rules: Use any of the following operations: basic operations (+ - x /), to the ...

Question 15

Try to make all numbers 1-30 using the digits 2, 0, 2, 5. Rules: Use all four digits exactly once. Allowed operations: $+,−,×,÷,! \text{ (factorial)}, !! \text{ (double factorial)}, !!! \text{ (...

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Questions tagged [number-property]

Joining Numbers Together [closed]

Mock binaries and divisibility

Same-size factorization

Cubic numbers out of cubic numbers

connections with numbers II

connections with numbers

Packing of 1 through 2025 into square with coprime adjacencies

Numerical crossword puzzles

Can you compute the common connection?

What is the next number according to some law? [duplicate]

Geometry Puzzle: Tangent Circles with Integer Radii

Making a 2n-digit number divisible by 9

Getting The Numbers 33 Through 99 Only Using 2, 0, 2, and 4 [closed]

How to get the numbers from 50 - 100 with the numbers 2, 0, 2, 4

Make numbers 1 - 30 using the digits 2, 0, 2, 5

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