# Questions tagged [formation-of-numbers]

For puzzles about forming numbers using other numbers and mathematical operations.

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### Numbers at the corners of concentric squares (part 2)

Put 4 distinct 1-digit non-negative numbers (A, B, C, D) on every vertex of a rectangle. Then put the last digit of the product of 2 connected vertices at the sides of the rectangle. Create a ...
357 views

### Numbers at the corners of concentric squares

Put 4 distinct 1 digit non-negative numbers (A, B, C, D) to every vertex of a rectangle. Then put the last digit of the sum of 2 connected vertexes at the sides of the rectangle. Create smaller ...
331 views

### Presti-digit-ation

In the spirit of lightweight prestidigitation, take a break to enjoy a gimmicky digital magic show. .'''''''''.---> _________________________ An ordinary 4-digit decimal : 3 9 1 8 :--->...
1k views

### Unique representation ID for 5-card poker hand using combination without sorting

There is a deck of 52 playing cards (e.g. poker cards). Assign every card a unique number (ID) at will. Every combination of 5 of these cards (a "hand") shall be represented by a unique result number, ...
836 views

### Arrange the numbers 1 to 19 in the circles

O---o---O / \ / \ o o o o / \ / \ O---o---O---o---O \ / \ / o o o o \ / \ / O---o---O Arrange ...
3k views

### 5008 out of the box

So I came across this puzzle somewhere: And the intended answer to it was: But that's pretty much straight forward. Thinking out of the box you can get a lot bigger "numbers" (values), for example: ...
277 views

### Create a 3x3 table with a specific rule

Take 9 distinct numbers from [0 to 9], then put the numbers to a 3x3 table, so : Each cell = Last digit of (sum of 2 numbers in the same row of the cell + sum of 2 numbers in the same column of the ...
376 views

### Use numbers 1-9 to yield 300000

Inspired by @Saiid's earlier question. Using $+,-,×,÷,$ exponents and factorials, use all the numbers $1-9$ (once and only once each) to generate $300 000$. Don't compose numbers from their digits, ...
2k views

### $7777/6666 = -212$

The title explains it pretty much, make $7777/6666$ equal $-212$. The following operators can be used. $+,-,*,/,\hat{},()$ Rules: Each number can only be used once You can move the numbers around ...
5k views

### Use the numbers 1-9 to equal 1150 [closed]

Not sure if this is too hard, but it's a more or less simple math puzzle. Use the numbers $1,2,3,4,5,6,7,8,9$ to get an answer of 1150. You can use the operators $+,-,*,/,\hat{}$ You can use ...
677 views

### (addition) 7 point star / heptagram

Place the numbers $1$ through $14$ onto each point, so that: A = 1 The sum of points in every line are equal, (A+I+J+C = B+J+K+D = C+K+L+E = D+L+M+F = E+M+N+G = F+N+H+A = G+H+I+B) A+B+C+D+E+F+G+1 = H+...
1k views

### Get 6 6 6 6 to equal 58 [closed]

$6 6 6 6 = 58$ $+ - * /$ and $()$ only 58 must remain as 58, (not 5 + 8, etc.)
2k views

### Finding the largest 7-digit number

Find the largest 7-digit number without its digits repeating, such that the number is divisible by all of its digits I found some constraints: • 0,4 and 5 cannot be included • The number found should ...
273 views

### Find a Strobogrammatic number, so if we square it, the result is a pandigit number

Find a Strobogrammatic number, so if we square it, the result is a pandigit number. Note : A Strobogrammatic number is a number when typed on a calculator, and the calculator is spun 180 degrees, ...
512 views

### Find the rule : triplet number into Positive Integer

These are triplets of numbers into positive integers: ...
1k views

### Making 1-50 from 2016

Make the numbers 1-50 using the numbers 2 0 1 6 in the given order. 1.You must use all four digits. 2.You may not use any other numbers. 3.You may use +, -, x, ÷, square root, squaring and cubing, ...
5k views

### What is the smallest set of letters that can spell any integer? [closed]

Today my 9-year-old nephew told me that he can spell any integer in English using only 9 letters. This is how he's doing it: ...
223 views

### modified 3x3 panmagic squares

This is a modified 3x3 panmagic squares. The square is divided into 2 triangles. Numbers 1 to 9 is arranged to upper triangles. Numbers 10 to 18 is arranged to lower triangles. All rows, all columns, ...
517 views

### Check digit number : Find the maximum number of distinct ways

Find the maximum number of elements in a set containing combinations of three digits (from 0 through 9) with the following rules: Each digit can be used more than once. Any two combinations in the ...
296 views

### The mathy square strikes back!

This is a follow-up question to Does this mathy square have any solutions? (And how many?). Consider a 7x7 grid of math operators o and numbers ...
1k views

### Does this mathy square have any solutions? (And how many?)

Consider a $5\times5$ grid of math operators and numbers that encodes 8 math equations: A + B = C = + + + + D + E = F + = = = = G = H + I There are 3 horizontal ...
697 views

### Can you express 1844 in a curious way? [closed]

Can you find integer values for $p$ and $q$ with $p,q\in\{0,1,2,\ldots,9\}$ so that the following equation holds? $p^q - q^p = 1844$
519 views

### Reveal all five equations

Five men enter a bar. 1st man order 1 Pepsi and 1 Cocacola 2nd man order 2 Pepsi and 1 Cocacola 3rd man order 3 Pepsi and 1 Cocacola 4th man order 4 Pepsi and 1 Cocacola 5th man order 5 Pepsi and ...
332 views

### It is related to a type of mathematics game

Start with two digits from $1\dots9$ to form a $2$-digit number. Multiply this number by a single digit from $1\dots9$. Add the result to another two digit number from $1\dots9$, and calculate the ...
2k views

### Expressing numbers using 0, 1, 2, 3, and 4

The least number that cannot be written using the numbers 0, 1, 2, and 3, each exactly once, and any combination of standard arithmetic operations (including factorials) is 41. What is the least such ...
320 views

### Number wheel Challenge!

Much like the Word-tank-wheel challenge, but numbers! Find a number that can 'rotate' in a way that the origin number and its rotations must be divisible (i.e. whole number) by the number of times it ...
512 views

### Find the next number in the sequence [closed]

One tough puzzle to solve : Find the next number in the sequence : 5,105,74,712,37,? Options are : a. 2008 b. 57 c. 507 d. 98 e. 44 What is the next number, and why? Puzzle ...
599 views

163 views

### Form n/2 with n amount of ANY number

For every $n, m \in \mathbb{N}; n,m > 1$, construct a method to produce $\lfloor\frac{n}{2}\rfloor$ using n ms. You can use: $$x+y$$ $$x-y$$ $$x*y$$ $$\frac{x}{y}$$ $$x^y$$ $$x\bmod y$$ \sqrt[k]{...
2k views

### Make 1 with any 3 of the same numbers

Is it possible to make 1 with any 3 numbers, all the same, such as using 3, 3 and 3 or 6, 6 and 6? Can you think of a proof which will work no matter which number it is? Trig functions allowed.
5k views

### How many consecutive positive integers can you make using exactly four instances of the digit '4'?

Starting at 1 (which is 4 - $\sqrt4$ - 4/4), how many consecutive integers can you make using exactly four instances of the digit '4'? Basic rules: Any operator symbol is "free". Any printed '4' ...
2k views

### Make the number 17 using only 2, 3, and 4 [closed]

Is it possible to make the number 17 using only 2, 3, and 4? Using the numbers only once and any operation, including factorials and other more advanced math. And it would have to be exactly 17.
How do you make 82 with the numbers $4, 5, 6, 7, 8, 9, 0$ and 8 dots. Get creative! You can use any mathematical operation, and the dots can be used in any mathematical way. No ratios. You must ...
Both $A$ and $B$ have numbered hats on their heads. $A$ and $B$ both cannot see his/her own hat, but they can see other one's hat. $A$ sees number on $B$'s hat as $5$ and $B$ sees $A$'s number as $4$. ...