Questions tagged [formation-of-numbers]

For puzzles about forming numbers using other numbers and mathematical operations. Use with [mathematics]

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Seven 2s with seven math operations

Linked to A four digit number using exact same 4 digits A number with same repeated digits is called a Repdigit or Monodigit number https://en.wikipedia.org/wiki/Repdigit Can you write an equation for ...
203 views

Everything needed to solve this cipher is on Puzzling Stack Exchange [closed]

5444 ---> lcxxfy 1906 ---> pstbqjilj 1582 ---> tcxvbpixrpejooat 1431 ---> dohhsfb 888 ---> uvqta 605 ---> noacomputers 618 ---> ylibz 425 ---> ...
4k views

A four digit number using exact same 4 digits

ABCD is a 4 digit number where A,B,C and D are 4 distinctly separate digits between 1 and 9. Using any of the following math operations and the digits A,B,C and D exactly once get the number ABCD. ...
2k views

78 views

Add operators to make the equation correct, and give 3 ways to do so

I'm trying to solve this puzzle: Add operators to make the following equation correct: 4 4 4 4 = 2. Give 3 ways to do so. You are allowed to use brackets if necessary, but no rearranging of numbers ...
273 views

This puzzle's value is 334

The 28th of october is valued by 40. This sentence is valued by 17. This paragraph is valued by 143. This puzzle is valued by 334. Can you give the value of Puzzling StackExchange?
150 views

Using the number 8 6 4 2 = either 19 or 17 [closed]

The numbers can only be used once. You can use any operator from BEDMAS.
119 views

Using the numbers 8642 = 9 [closed]

Using any calculation in BEDMAS use the numbers 8645 = 9 Numbers can only be repeated once.
177 views

3k views

When you take away two

I am an odd number. When you take away two, I become even. What am I? Edit: @hexomino got my original answer but I have come up with another valid answer. Edit 2: @QuantumTwinkie got my other ...
2k views

Create an equation using the following numbers and mathematical symbols: 4,2,1,2,4,+, =

Create an equation using only the following numbers and mathematical symbols: $$4,2,1,2,4,+,=$$
56 views

A Dices Probability Riddle [duplicate]

Bob (A), Steven (B) and Joe (C) were playing with dices, each one of them made his own dice and wrote a number between 1-6 on each side of his dice. After playing for a while they've noticed that : (...
2k views

Create integers using 1, 2, 3, 4, 5, 6, 7 and +, -

There are numbers $1, 2,3,4,5,6,7$ and signs '$+$' and '$-$'. Using only these numbers and signs, you can compose expressions and calculate the sum (difference). Concatenation operation is not valid. ...
160 views

What is a Special Prime Number™?

This is inspired by the What is a Word/Phrase™ series started by JLee with a special brand of Phrase™ and Word™ puzzles, now with numbers. If a number conforms to a special rule, I call it a Special ...
496 views

What is a Chemical Number™?

This is inspired by the What is a Word/Phrase™ series started by JLee with a special brand of Phrase™ and Word™ puzzles, now with numbers. If a number conforms to a special rule, I call it a Chemical ...
224 views

May Make $\frac5{2020}$ 2020

For May 2020, try to create $\dfrac{5}{2020}$ using the least possible number of integers in the set $\{1,3,4,6,7,8,9\}$. $2$, $5$ and $0$ are not allowed. Example: \dfrac{4+1}{3\left(673+\frac13\...
884 views

Four fours to get $\pi$ [closed]

Four fours is a famous puzzle (made trivial with logarithms). For this puzzle, we take inspiration from Glen O's challenge from a few years back. The rules here are slightly different, but the goal is ...
1k views

Prime to number conversion

This puzzle relates to Prime to Prime: Get all first 25 Prime Numbers using up to 4 Primes and its sequel Prime to Prime Sequel Using any three of the first 4 prime numbers (2,3,5 and 7) and the ...
122 views

Name that node #2

What is the value of the unknown node? Previous Name that node #1 (Beginner's Level Puzzle)
124 views

Name that node #1 (Beginner's Level Puzzle)

While Puzzling.SE has some extremely clever and difficult puzzles that are being solved by people whose intellect amazes me, I wanted to make some graph puzzles that were specifically meant for ...
415 views

I'm a number with a special product, so name me when you think you've got it

In the blocks that come before, their special product tells us more. To guess my scheme you'll need calculation, but only little tests of recreation. Each block contains atoms strong as Thor, ...
Rules: Make the numbers 1-100 using eight 8s Use the operations + - * / exponentiation and ! No Rounding as in $(\sqrt{88}+8*8+8+8+8)/8= 12$ No using other digits Multi digit numbers ...