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Questions tagged [formation-of-numbers]

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

3
votes
1answer
538 views

Can you find the pattern?

If the following are true: $4+7+2 = 281435$ $7+3+9 = 212781$ $6+2+7 = 121456$ $2+8+5 = 164036$ Then what would the following equal? $8+4+6\ =\ ?$ Can anybody check my work? I ...
-4
votes
1answer
144 views

Find relation between 2 numbers (username and password)

I have a two sets of Usernames and passwords as follows: User --> Password 1456 --> 3473 1360 --> 3377 Now I have to find the password for 1301. Could anyone please help find the relation (it is ...
1
vote
1answer
219 views

Shortest path from one $\to$ ten with a twist - Updated

NOTE: The rules have been updated to cause the nature of the puzzle to be as intended. I will upvote the answer which was given before the change, but I look for both alphabetic and math operations to ...
8
votes
2answers
6k views

Make 10 out of 1, 1, 5 and 8

A friend of mine shared a puzzle with me this evening. Using the numbers 1, 1, 5 and 8 exactly once, and the basic operations (+, -, /, *) and (optionally) parentheses, form an expression which ...
2
votes
2answers
173 views

Hexadecimal = n times decimal

Was explaining hexadecimal numbers to a friend and this made me wonder: "Is there an hexadecimal number x that is a whole number n times its decimal value ?" So for example the hexadecimal number ...
18
votes
5answers
6k views

How to get 5 from 0,0,0 and 1?

Can you use the digits 0,0,0 and 1 each only once in a mathematical expression for the number 5 using only common mathematical symbols with at least 1 mathematical symbol between each number?
11
votes
3answers
1k views

Find the correct math words to equals the intended number

I am testing a new puzzle. I hope the puzzles are intersting. Example: 3 7 7 2 4 = 40 Answer: two(3) hundred(7) divided(7) by(2) five(4) = 40 Rules: Find the correct words. Numbers of letters have ...
14
votes
3answers
1k views

If 6 was 9, or 100 was 64, or M was N

         Now if a 6,          Turned out to be 9,          I don’&...
18
votes
1answer
1k views

New Mathematics forever

This has been (renamed and) refocused on boboquack’s unforeseen solution, which deserves its own puzzle. Right when you thought the good old days of New Mathematics were safely dusted, ...
5
votes
1answer
281 views

Sticking Numbers

Try to figure out the answers from the 2 patterns below. Find all the 10 digits first. Rotate if necessary. A: What is the missing number? [?] [10] [11] [9] [11] B- What is ...
7
votes
1answer
296 views

Arrange numbers to the triangles, so the sums are equal to S

Rules: Arrange numbers from 1 to 11, and each number can appear max twice. The numbers are arranged, so that any 3 numbers which forming an up-triangle sum to the desired number (S). A equal sign ...
4
votes
2answers
130 views

Representation of Mo-roman numerals

This continues the spirit of Mo-roman numerals started by humn What is/are the natural number(s) that has/have the most different representations in mo-Roman numerals and what is the number of ...
12
votes
2answers
461 views

A mo-Roman sampler

    Pluck some relatively easy mo-Roman mini-puzzles while there’s relatively easy pickin’s. What two English words, taken as mo-Roman numerals, form the same number? ...
12
votes
2answers
838 views

How many consecutive integers can you make using only four digits?

In the spirit of the classic four fours, I wonder what's the optimal set of four numbers? Your goal is to make the most consecutive integers using four digits of your choice. Pick four: $0,1,2,3,...
18
votes
2answers
933 views

Self-intro to mo-Roman numerals

Here come mo -Roman numerals — just like Roman numerals, only mo’ so.   (Explained as we go.)   What number can spell itself in two different ways ...
22
votes
6answers
11k views

The 10,958 Problem

Here is the task: Write down 10958 using all 1-9 digits in ascending order and only one time. You are allowed to: 1) group digits into numbers 2) use 5 basic operations: + - * / ^ ("^" ...
-6
votes
4answers
171 views

Find 25 using 6, 25, 9, 8 only

You can only use these numbers once, so not square root or cubed root or anything else. Good Luck!!
3
votes
5answers
769 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
388 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
316 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
364 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
156 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, ...
-2
votes
2answers
165 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
813 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]...
25
votes
4answers
22k 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 ...
36
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
393 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 ...
18
votes
16answers
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
367 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
281 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
135 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 ...
32
votes
5answers
5k 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
41k 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
13k 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
229 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
676 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 ...
24
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 $2*7-10$.
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 ...
6
votes
2answers
471 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
147 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
148 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
346 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
245 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
147 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
652 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
904 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
1k 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 ...