Questions tagged [formation-of-numbers]

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

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5
votes
4answers
403 views

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 ...
3
votes
4answers
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 ...
12
votes
1answer
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 :--->...
17
votes
6answers
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, ...
4
votes
1answer
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 ...
5
votes
8answers
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: ...
4
votes
1answer
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 ...
1
vote
9answers
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, ...
1
vote
2answers
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 ...
6
votes
18answers
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 ...
6
votes
4answers
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+...
0
votes
10answers
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.)
3
votes
2answers
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 ...
3
votes
2answers
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, ...
3
votes
1answer
512 views

Find the rule : triplet number into Positive Integer

These are triplets of numbers into positive integers: ...
5
votes
4answers
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, ...
40
votes
16answers
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: ...
1
vote
2answers
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, ...
5
votes
1answer
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 ...
4
votes
2answers
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 ...
14
votes
4answers
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 ...
-2
votes
3answers
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? $p^q - q^p = 1844$
5
votes
2answers
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 ...
2
votes
2answers
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 ...
4
votes
1answer
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 ...
4
votes
3answers
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 ...
6
votes
4answers
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 ...
13
votes
2answers
599 views

Help me find my friend!

I need your help! My friend has gone missing and I have no clue where he could be! However, he did manage to get a message out to me: Kidnapped. Send help. I am here: port town. $\left\lfloor\...
10
votes
3answers
1k views

Two functions that can't be applied in different order to arrive at same result

Here's my puzzle: Write two unary functions f, g and provide an input x so that only the ...
-5
votes
4answers
442 views

A Wonderfully Tricky way of Making any Positive Integer [closed]

Make all positive integers, starting from $1$, using: Exactly four $4$'s (and no other digit), concatenation being allowed, Any standard mathematical symbol(s) and operation(s) not listed below. ...
27
votes
11answers
6k views

Make 11 from five identical digits

At a tender age my father introduced me to an arithmetic game: making the number 11 from five single digits using only the basic operators listed here: ...
33
votes
21answers
12k views

3:3! It's a football score! [closed]

Given to me, by a friend: How would you make 20, using two threes? You may use any basic operation. And others, such as square roots (the symbol), factorials, etc. Any operation is allowed. Just ...
1
vote
1answer
418 views

Riddle with functions [duplicate]

The following is a riddle, that is not so easy as it seems. Using the numbers 1, 3, 4, 6 only once, you must use any of the functions (addition, multiplication, division, subtraction) in order to form ...
11
votes
2answers
333 views

Make a certain number with an unusual calculator

The Kasio Kool-Kalk™ is a poorly-designed calculator with only two buttons, labelled $[A]$ and $[B]$. Pushing $[A]$ replaces the currently displayed number $x$ with $2-\frac{1}{x}$. Pushing $[B]$ ...
7
votes
2answers
564 views

Please make x and y and z

This puzzle continues "Please make 1 and 2 and 4". A mathematical expression is feasible, if it obeys the following rules: Any real number may be used One may use brackets "(" and ")" to structure ...
0
votes
1answer
1k views

24 game… with exponents!

You may have seen the 24 game where you take four numbers and try to make 24 using the numbers and mathematical operations. However, I present a twist on the 24 game: with an exponent. Here are the ...
14
votes
1answer
2k views

Hello, I am a pretty big number. Add a line to make me many things

I am a pretty big number: Here are a few challenges for you: Add a line to make me a millennium. Add a line to make me a millennium and ten. Add a line to make me a century and one. Add a line to ...
1
vote
4answers
892 views

Use six 6s in an expression that equals 1,000

Given: six 6s Goal: Construct an expression with value $1,000$ Rules: Use all six digits in each expression. No other digits are allowed. Concatenation of digits is allowed. One horizontal ...
9
votes
3answers
3k views

A breathtaking way of making every possible positive integer

This is a follow-up question to my older puzzle "A truly amazing way of making the number 2016" and to my other older puzzle "A truly amazing way of making every possible positive integer". My ...
0
votes
3answers
256 views

Fill in the parentheses [closed]

$()+()+()+()+()=30$ How can you fill in the parentheses with the numbers $1, 3, 5, 7, 9, 11, 13$ to make the above equation true? Repeats are allowed, but you must fill in all of the parentheses! ...
7
votes
5answers
1k views

Simple but interesting math puzzle [duplicate]

Four numbers are available: $1$, $3$, $4$ and $6$. Every number must be used once and only once with (some of) the operations $+$, $-$, $\times$, $\div$ to form the number $24$. It's from the book "...
7
votes
4answers
2k views

A truly amazing way of making every possible positive integer

This is a follow-up to "A truly amazing way of making the number 2016": For every positive integer $n$, find a mathematical expression that yields the value $n$ while obeying the following rules:...
13
votes
16answers
10k views

A truly amazing way of making the number 2016

Find a mathematical expression that yields the value $2016$ while obeying the following rules: Each of the digits $1,2,3,4,5,6,7,8,9$ is used exactly once Decimal points are allowed You ...
2
votes
2answers
376 views

90s Number Puzzle

So here's how it works: Take the digits from 1991. You can use the digits in any order, only once (you can't make a 19 or 91), with any operation sign to get answers between 1-100. For example: $4=(1+...
-1
votes
2answers
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]{...
12
votes
8answers
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.
28
votes
9answers
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' ...
0
votes
11answers
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.
-5
votes
3answers
1k views

Make 82 With Numbers and Dots

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 ...
12
votes
3answers
652 views

Who will find the number on their own hat first?

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 $4$. ...