Questions tagged [formation-of-numbers]

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

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2
votes
5answers
951 views

Make 12 with 1, 5, 19, 10

How can you make the number 12 with just the numbers 1,5,19,10? You can only use each number once, and can only use subtraction addition multiplication and division.
8
votes
1answer
395 views

Arrange (+,-,x,/) into the upsilon grid

Put operators $(+,-,×,/)$ into the squares. Each operator must appears exactly 3 times to make the operations correct. C is a constant. No BODMA rules ((×) and (/) is NOT HIGHER than (+) and (−)), do ...
4
votes
2answers
352 views

Arrange numbers 1 to 9 into the upsilon grid

Arrange numbers 1 to 9 into the octagon, so the operation is correct. C is a constant. Do the math operation in sequence, ($×$) and ($/$) is NOT HIGHER than ($+$) and ($-$).
9
votes
4answers
371 views

The pre-alpha calculator

You are given a rudimentary prototype of a calculator with only the following keys: 0 1 2 3 4 5 6 7 8 9 + - × ÷ = The display has place for 10 digits and is initially showing ...
0
votes
2answers
173 views

Robbers - Make 24 [closed]

The make-24 puzzle is an oldie, but a very fun one at that. Given four different numbers, produce—through a sequence of operations upon only those four numbers—the number twenty-four. For example, ...
-1
votes
2answers
301 views

Coppers - Make 24 [closed]

The make-24 puzzle is an oldie, but a very fun one at that. Given four different numbers, produce—through a sequence of operations upon only those four numbers—the number twenty-four. For example, ...
6
votes
7answers
862 views

Making 4 with 4 ones (with a twist!)

This puzzle is all about making 4 with 4 ones, but with certain constraints. Allowed operations: $-$ Subtraction $-a$ Negation $\times$ Multiplication $\div$ Division $\sqrt{a}$ Square Root $\sqrt[b]...
27
votes
4answers
32k views

Create all numbers from 0-100 only using all of 1,2,3,4 and 5

Create all numbers from 0-100 only using 1,2,3,4 and 5. No repeats and you have to use each number. Also, you can use any operation. I've only gotten to 50 by pure brute force. I think that this might ...
37
votes
5answers
6k views

Making 103 from 4 zeroes

As the title suggests, the puzzle here is making the number 103 by using exactly four 0s and the following operations: $+$ Addition $-$ Subtraction $\times$ Multiplication $\div$ Division $\sqrt{a}$ ...
9
votes
3answers
413 views

Sum self enumerated digits

Please fill in the entire summations for lines 4 through 9 and just the total for line 1,000,000.         1.     1   =   1   ...
15
votes
4answers
1k views

February 2017 golf

How many minutes are there in February 2017? This is "puzzling golf". The shortest correct answer wins. PS: The puzzle is not so much to compute the result, but rather to express it in fewer than 5 ...
19
votes
17answers
9k views

Number 88 from the digits 2, 0, 1 and 7?

Can you use the digits 2, 0, 1 and 7 each only once to create the number 88?
4
votes
2answers
372 views

The Six Symbols

The professor turned to me and said, "I believe that all numbers in mathematics can be expressed with only 6 symbols." "A bold claim," I replied. "I suppose the you want all numbers to be encoded in ...
2
votes
1answer
303 views

Most consecutive positive integers using two 1s

Using two 1s, try to come up with the most consecutive positive integers. Allowed operations: Addition Subtraction Multiplication Division Concatenation Square Root Radical Factorial Floor and ...
5
votes
1answer
136 views

Tangled keyrings puzzle

Can you assign a unique number to all the keyring chains below and sort them accordingly? After you finished, can you think of arrangements that give some other numbers, different from the 15 cases ...
33
votes
5answers
7k views

Rendering the number 10,958 with the string 1 2 3 4 5 6 7 8 9

Brazilian mathematician Inder Taneja has found a way of expressing every number between 1 and 11,111, except 10,958, by inserting mathematical operators in between the numbers 1 2 3 4 5 6 7 8 9 and ...
9
votes
7answers
48k views

Make numbers 1 - 32 using the digits 2, 0, 1, 7

This is similar to the "Four fours" puzzle, but using the digits 2, 0, 1 and 7. Rules: Use all four digits exactly once Allowed operations: +, -, x, ÷, ! (factorial), exponentiation, square root ...
14
votes
5answers
17k views

10 9 8 7 6 5 4 3 2 1 = 2017

Add the four basic operators $\times\div+\,\;-$ and optionally brackets to: $10 \quad 9 \quad 8 \quad 7 \quad 6 \quad 5 \quad 4 \quad 3 \quad 2 \quad 1$ To get the total $2017$. Rules: Look for ...
4
votes
1answer
235 views

The Autonumerigram Challenge [duplicate]

Some phrases both refer to a number, n, and are comprised of n alphabetic characters. I call any such phrase an autonumerigram. For example, four has 4 letters seven plus seven has 14 letters ...
12
votes
3answers
698 views

Self-Factorial Number

Self-factorial number is the number where its digits' factorials summation is equal to the number itself. But there are only a few amount of them. For example; $1=1!$ $2=2!$ $145= 1!+4!+5!$ So ...
26
votes
9answers
8k views

A clock for 2017

Design a clock where each number from 1 to 12 is obtained as an arithmetical operation using each digit of 2017 exactly once: for example, 4 could be made as $2\times 7-10$.
3
votes
5answers
2k views

Minimum difference with Digits

You have digits from $0$ to $9$, where you have to use every digit only once. create 2 numbers from the digits so the difference is minimum. example : $30568 - 29471 = 1097$ What is the lowest ...
8
votes
2answers
565 views

Maximum Result with Digits

You have digits from $0$ to $9$, where you need to use every digit only once, and you have only one operator (multiplication, $*$). You may combine/join digits to create a bigger number as shown below:...
3
votes
2answers
160 views

Arrange numbers to the equations, so if we turn the equations upside down, they are still right

_ + _ = _ _ + _ = _ _ + _ = _ _ + _ = _ Fill the blanks with numbers above, so: The 4 additions are right. All numbers must be used. If we turn the additions upside down, they are still right, ...
-3
votes
2answers
208 views

Find the correct sign

This is a question in a primary school book as a riddle. How can we put any mathematical sign (addition , subtraction, multiply and division) between five 5s to get the answer 66? 5 5 5 5 5=66
-5
votes
1answer
179 views

3 is the magic number [closed]

I am wondering what is the answer to these if the magic number is 3. So like.. 1 1 1=3 2 2 2=3 3 3 3=3 4 4 4=3 5 5 5=3 6 6 6=3 7 7 7=3 8 8 8=3 9 9 9=3 10 10 10=3
4
votes
1answer
156 views

Numbers at a flower-like circles

Above picture is a flower-like circles with digits to each intersection which follow the rules: A circle and its center must contain all of the digits from 1 to 7. I have put some numbers to some ...
4
votes
1answer
438 views

Arrange numbers and operators to the magic triangle

Note : A # B = A*10 + B Arrange the numbers 1 to 9 to green triangles, and arrange operator (+,-,x,/,^, and #) to the white triangles, so the math operations below are equals. (((A op1 B) op2 D) op3 ...
4
votes
3answers
341 views

Arrange numbers to a 6 point star

Arrange the numbers (1,2,3,4,5,6,7,8,9,11,12, and 16) to replace the letters, so every 3 vertices which form a triangle have equal sums.
5
votes
1answer
155 views

Arrange numbers and operators to piano-keys

Let a # b = a*10 + b Example : 5 # 5 = 55 9.5 # 3 = 98 Arrange numbers 1 to 7 to each piano's-white-keys. Then arrange operators (+,-,x,/, and #) to each ...
5
votes
4answers
659 views

All digits with one operation

I can't find this very easy, simple puzzle here, so here goes: Using all ten digits from 0 to 9 exactly one time, find an equation (using =, not !=, don't be silly) that uses only one of the ...
5
votes
3answers
909 views

Ane and her block toys

Ane is a very smart kid. She has 9 number blocks [1] to [9], and 2 operation block [+] and [x]. Today She is playing with her blocks. She is so happy after arranging her blocks, then perform the math ...
8
votes
2answers
2k views

Can you solve the 7x7 (sudoku-ish) centered sums puzzle

I have come across this puzzle a few times in competitions and rally's, and it has troubled me because I cannot seem to find a good approach to solving it, either programmatically or numerically. And ...
5
votes
4answers
402 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
353 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
327 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
790 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
274 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
375 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
662 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
270 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
508 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: ...