Questions tagged [formation-of-numbers]
For puzzles about forming numbers using other numbers and mathematical operations. Use with [mathematics]
32
questions
-2
votes
0
answers
86
views
Find the missing number in 3×3 square [closed]
8 12 9
10 7 20
3 10 ?
Find the missing number from the 3×3 square.
-1
votes
3
answers
143
views
2,3,6,7 to get 10 [closed]
How do I use the numbers 2,3,6,7 to get 10? You can also make numbers like 23 or 76 too.
- 29
8
votes
1
answer
1k
views
Making 1353 using Four fours
As the title says, the goal for this puzzle is making 1353 out of simply 4, 4, 4 and 4. Concatenation is not allowed. Here are all of the allowed operators.
Addition (+), Subtraction and negatives (-)...
- 383
-4
votes
3
answers
162
views
Use 1 6 7 8 (all numbers) to equal 2 [closed]
Create an equation using 1, 6, 7 and 8 to equal 2.
Can use brackets, plus, minus, subtract, multiply.
- 11
5
votes
1
answer
145
views
Number relations in a number table
I found this puzzle in a school study group. Choices are 9, 10,11, 12, 13.
$$ \begin{array}{|c|c|c|c|} \hline 22& 22 & 23 & 24 \\ \hline 22 & 32& 41& 52\\ \hline 23 & 41 &...
- 53
-2
votes
2
answers
224
views
How do you make numbers 1 - 100 using the digits "2 0 2 4"? [closed]
I'm trying to complete this "2024 Challenge", but I'm still missing quite a lot of numbers. I need your help to finish this challenge. All answers are appreciated.
Rules:
Use all 4 digits ...
1
vote
0
answers
177
views
Can you obtain a given set of numbers by halving a chosen number? [closed]
Given a set of numbers, I want to check if it is possible to produce the full set of numbers by repeatedly splitting one single starting number into its halves and doing the same for each of the ...
- 39
6
votes
4
answers
416
views
Approximate ln(2) out of small numbers
Given numbers 1,2,...n, the goal of this puzzle is to make a number as close to the mathematical constant $\ln(2) ≈ 0.69314718055$ as possible.
Rules
You can only use the four mathematical ...
- 2,423
-2
votes
1
answer
111
views
How to make all the numbers ranging from 1-30 only using the numbers 1, 5, 0, 4 [closed]
You can use the numbers 1, 5, 0, and 4 but you can't square and cube, you can't use any other numbers, you can't use the numbers more than once, your answer can't be rounded, and you MUST use all the ...
- 11
0
votes
1
answer
165
views
Getting The Numbers 33 Through 99 Only Using 2, 0, 2, and 4 [closed]
How do you get the numbers 33-99 by using the numbers 2,0,2,4
- 29
5
votes
4
answers
441
views
How to make 2012 by using 2, 0, 1, 2?
How to make $2012$ by using $2, 0, 1, 2$?
Allowed Operations:
Addition, Subtraction, Multiplication, Division, $!$ (factorial), subfactorial ( $!n$), primorial (product of the first $n$ primes), ...
- 285
6
votes
4
answers
762
views
How to get the numbers from 50 - 100 with the numbers 2, 0, 2, 4
All I need is 56-59, 69, 73, 75- 77, 79, 86, 90-94, 99. I've done the rest but I would love to hear other solutions.
Rules:
Use any of the following operations: basic operations (+ - x /), to the ...
- 79
-2
votes
1
answer
146
views
Make numbers 1 - 30 using the digits 2, 0, 2, 5
Try to make all numbers 1-30 using the digits 2, 0, 2, 5.
Rules:
Use all four digits exactly once.
Allowed operations: $+,−,×,÷,!
\text{ (factorial)}, !! \text{ (double factorial)}, !!! \text{ (...
- 438
0
votes
1
answer
97
views
Insert operators into 3 5 7 = 7 [closed]
How can you insert any math symbol/operation () ! - + x / square root etc into 3 5 7 = 7 without adding any numbers or changing the order? For example, 3-7+5=1 or 3+7-5=5.
Also, try to solve 3 7 5 = 2,...
- 27
18
votes
4
answers
5k
views
Make 27 using 1, 1, 1, 1
Make the number 27 using 4 instances of the digit 1. You must use all 4 digits to make it count.
Here are the allowed operators:
Addition (+), subtraction (-), multiplication (*), division (/)
Square ...
- 383
4
votes
2
answers
513
views
Make expressions equal to 6 using exactly four 4s
You must use all four 4s.
You may use addition (+).
You may use subtraction (-).
You may use multiplication, such as with asterisks (*) and/or grouping symbols.
You may not use any division.
You ...
- 1,788
3
votes
1
answer
273
views
Constructing 2024 from the first 7 natural numbers
Can you use each number 1, 2, 3, 4, 5, 6, 7 exactly once, the four operations +, -, *, / and the parentheses to construct the number 2024? Bonus: can you find multiple distinct solutions? No computers ...
- 36.3k
3
votes
2
answers
368
views
Approximate e out of small numbers
Given the numbers 1, 2, ..., n the puzzle is to try to make a number as close as possible to the mathematical constant $e$ using only the four mathematical operations +, -, *, / and parentheses (...
- 7,845
12
votes
6
answers
10k
views
Make numbers 1 - 30 using the digits 2, 0, 2, 4
Try to make all numbers 1-30 using the digits 2, 0, 2, 4.
Rules:
Use all four digits exactly once.
Allowed operations: $+, -, \times, ÷, !$ (factorial), x^y (exponentiation), √ (square root).
...
- 137
8
votes
1
answer
913
views
Escape Room Puzzle: numbers in Christmas trees
I was sent this puzzle by a friend who's recently attended an escape room, but it's really not coming to me.
I wondered if anyone had seen similar puzzles and could suggest an answer?
- 183
6
votes
1
answer
364
views
Add as few plus signs as possible to make equation true
To allow new users to solve this puzzle and earn reputation points, I encourage all users whose reputation is 200 or more to not post an answer until 48 hours after this question is posted. Thank you!
...
- 12.7k
18
votes
11
answers
5k
views
How to solve 1 2 3 4 5 = 5 4 3 2 1 (insert five pluses to make it equal)? A thorough solution needed
I consider it an amazing though very challenging puzzle:
1 2 3 4 5 = 5 4 3 2 1
One must insert exactly five pluses (i.e. five addition signs) somewhere between those ten displayed figures in such way ...
- 595
-2
votes
1
answer
320
views
Create numbers from 1-100 using 1846
Create all numbers $1$ to $100$ using equations made up of $1,4,6,8$.
Rules:
Use all four digits exactly once
Allowed operations: $+,\,-,\,\times,\,\div,\,!$ (factorial), exponentiation ($a^b$), ...
- 29
10
votes
4
answers
2k
views
A Prime Number equation using all nine digits once
Create an equation with the following conditions
All numbers must be one or two digit prime numbers
You can only use + and - and =
No other math operators
You must use all the nine (single) digits (...
- 6,627
-4
votes
1
answer
247
views
4
votes
13
answers
4k
views
Let's make a huge number with only tiny numbers
Using only three 1s and two 2s (i.e. 1,1,1,2,2), can you generate the number 55? You can use all mathematical operators you know, such as floor function, factorial, powers/indices*, etc., but ...
- 99
2
votes
1
answer
145
views
If 123x45 = 1, 22+222=0, 8979:4=5, 56319=2 what is 781-32=?
If 123x45 = 1, 22+222=0, 8979:4=5, 56319=2 what could be the solution to 781-32=?
Found it on an maths board and became desperate over time.
- 29
5
votes
1
answer
236
views
Number encoding puzzle
An "ancient" writing system for numbers was discovered:
How would the number 75 be represented with this code? (Two symbols)
I think I made it too hard, here are some hints:
- 153
3
votes
2
answers
214
views
How can this equation make sense?
Think a bit creatively and tell me why is this equation correct
- 6,627
-2
votes
1
answer
283
views
Creating a high number from this grid using minimal mathematical operations
I'm creating a puzzle (pictured below). From this grid, how could I output a 10-digit number? The tiles cannot be moved or changed.
Instruction-wise, I would like to provide my players with some ...
- 595