# Questions tagged [formation-of-numbers]

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

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### Making π from 1 2 3 4 5 6 7 8 9

There have been two other questions here and here that are similar to this one, but this changes the rules up a little. Your job is to approximate $\pi$ using the sequence of digits (in order): 1 2 ...
136 views

### What is wrong about the following code?

A colleague asked me this question What is wrong about the following code: ...
1k views

### Euler's identity

Warning: this question requires knowledge of complex numbers. An Euler's identity is an identity, in which each of the following appears once and only once: the constant $0$: neutral element for ...
100 views

### How do I solve this puzzle?

I am trying to answer this puzzle - which of the five potential answers is correct, and why? This test comes from Metropol iq1 book
100 views

### How do I solve this numerical puzzle?

I am trying to answer this numerical puzzle - which of the five potential answers is correct, and why? 6*3*5 = 183033 5*4*3 = 201532 7*2*7 = 144928 8*2*9 = ? ...
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### I want an exact value of Pi

Use 1, 2, 2, 2 (Each number used exactly once) to form π. I want an exact value of π, not any approximation. Available operators: + - * / ( ) ^ ! You can use any one of them for any times. Hint:...
582 views

### How to make the number 49?

You've to start with $1$ and can use each of the following operations at most once. You can do the following in any order you like: 1) Add $2$. 2) Add $3$. 3) Add $5$. 4) Multiply $2.$ 5) ...
223 views

### What is the next number in the sequence and why?

7 4 11 2 14 5 18 3 21 ? Find the next number in the sequence?
192 views

### SAME DIGIT NUMBER PUZZLE

You have 5 numbers 1, 9, 3, 5, and 7 you need to arrange these number like Rules create 2 pairs from numbers above keep one of the number in the middle then apply this law ...
640 views

### Number Equation Matrix

Can somebody please solve this? My daughter's school teacher gave her this puzzle to solve at home. But to me it seems a little out of order, and that's why I am asking here for help.
92 views

### Find the missing number (number sequence puzzle) [duplicate]

Find the missing number 56784 = 4 11111 = 0 72348 = 3 88652 = 5 88811 = 6 75213 = 0 65465 = 3 62257 = ? I found this quiz in an archive of our company's ...
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### Make 38, 44, 46 using 2,3,8,7?

Using BODMAS/BIDMAS* and the numbers and signs 2,3,7,8, (), -,+,÷,× can you make 38, 44, 46. You can only use each number once. I can't figure it out myself Brackets Order Division Multiply Add ...
5k views

### Make 2019 with single digits

This puzzle is inspired by a puzzle by @Andrew, where the goal is to make 1998 from a minimal amount of 8s. This is a variation of the puzzle, where the goal is to make 2019 using a minimal amount of ...
128 views

### How do you make 29 only using the numbers 1 2 3 4 [closed]

How do you make 29 with only using the numbers 1 2 3 4? I have tried a lot of solutions and please remember that you can't use the number 5
148k views

### 1 2 3 4 5 6 7 8 9 = 100

The sequence of numbers $1\ 2\ 3\ 4\ 5\ 6\ 7\ 8\ 9$ has the property that you can insert mathematical operators in between the numbers from $1$ to $9$ and make the expression evaluate to 100. For ...
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### Squares inside a square

Distribute the digits from 1 to 9 to a 3x3 square, such that you reach as many square numbers as possible. A valid square number in the 3x3 square is either a single digit square number or is build ...
206 views

### Find pattern for new equation in number sequence

I saw this puzzle on this address. $3+5+7=152181$ $4+5+6=202461$ $3+4+7=122172$ $9+4+5=364518$ $8+6+8=?$ I know that first $4$ digits are $4864$. How could I find last $2$ ...
177 views

### Make $2471$ out of first seven powers of two

Can you make $2471$ using first seven powers of two: $1,2,4,8,16,32,64$, each exactly once? Only the basic operations are allowed: $+,-,\times,\div$, and parentheses $(\space)$. ...
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### Make a formula to get the highest score

In this puzzle you need to obtain the highest score with the following rules 1) choose two digits from 1, 2, 3, 4, 5, 6, 7, 8 and 9. These digits are represented by two letters, let us say $T$ and $M$...
571 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:...
627 views

### Hiker's Cabin Mystery | Pt. II

See Part I | See Part III Nice one, @GarethMcCaughan! Finally, you've gotten into his computer using the password you managed to decode from his clues... but there's another issue! There is a ...
35k 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 ...
132 views

### He said yes..she said no..they went back and forth..they agreed to [closed]

To call it a Prime. S, N, O are 3 distinct digits that are to be determined by you so that their conclusion is right Full concatenated number: SNOSNOS
936 views

### SafeCracker #3 - We've Been Blocked [closed]

Our Last Safe To Conquer Ok, team, this one might give us a little trouble. Nothing we can't handle though... let's go... This safe model is "The NevaCrak 9000" - the most secure safe there is. ...
18k views

### Combine 3, 3, 5 & 7 to get 24

Using operators plus, minus, multiplied by and divide by, and as many brackets as you want, can you do a formula which uses 3, 3, 5 and 7 to make 24? Each number must be used and can only be used ...
337 views

### The result is 7 game

The goal of this game is to find the lowest score for the 10 equations below. 0 ? 0 ? 0 ?...
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' ...
121 views

### some sequences are awesome!

My name is Awesom$\Sigma$ Sequenc$\Sigma$. Nice to meet you all :). I am new here. You can either use my first name or last name to address me. My hobbies include visiting new places. I usually ...
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### 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 $2\times 7-10$.
### Construct $\sqrt{3}$ using every natural number
Construct $\sqrt{3}$ using every natural number $n\in \mathbb{N}$ (1, 2, 3, 4...) exactly once and the operations addition ($+$) and division ($\div$).