Questions tagged [formation-of-numbers]
For puzzles about forming numbers using other numbers and mathematical operations. Use with [mathematics]. Puzzles using this tag should carefully specify the allowed operations.
471 questions
2
votes
5
answers
375
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Can you get 100 using only 9,1,6,6 each once? [closed]
I was playing Math Flux and the winning goal was 100. We had combined digits out so we can combine 2 digits together
Can you get 100 using the digits 9,1,6,6 using only each digit once?
- 39
11
votes
1
answer
727
views
Make 101520 with 6 6's
Make the number 101520 with 6 6's.
Rules:
All 6's must be used exactly once
The operations allowed are addition (+), subtraction (-), multiplication ($\times$), division ($\div$), exponents and ...
- 3,136
-1
votes
1
answer
252
views
I count fractions of rotation and have two digits, what AM I?
I count fractions of rotation and have two digits, what AM I?
I use letters over digits.
I don't use a pair of digits for my most significant digit from one of my series.
I can use any one of my ...
-2
votes
1
answer
174
views
What equation equals 20 but only the numbers 1 2 0 3 can be used and they can be only used once and no other numbers can be used [closed]
I have tried grouping the numbers but that doesn’t work
6
votes
12
answers
3k
views
Seven nines to make ninety
Use seven 9s to make 90.
The allowed operations:
$+, -, \times, \div, x^y, \sqrt{\square}$, parentheses
$\sqrt[\square]{x}$ is not allowed. (e.g. $\sqrt[9]{9^{9
}}=9$ isn’t allowed.)
Have fun!
- 2,572
1
vote
4
answers
183
views
From 1 – 6 and 7 – 10 make 37
1 _ 2 _ 3 _ 4 _ 5 _ 6 = 7 _ 8 _ 9 _ 10 = 37
Programming Operations are allowed. (+, -, ×, ÷, ^, parentheses)
I made this simple puzzle.
- 2,572
13
votes
2
answers
610
views
Make 2025 using 3 single digits
Make 2025 using exactly 3 single digits (not necessarily different).
Rules:
Allowed operations: $+,−,\times,\div,!$ (factorial)
Parenthesis are allowed and can be interpreted as binomial coefficient.
...
- 13.1k
8
votes
8
answers
2k
views
Make 987 using 1, 3, 5, 7, 9
Make the number 987 using digits 1, 3, 5, 7, 9.
Rules:
Use all five digits exactly once.
Allowed operations: $+,−,\times,\div,!$ (factorial), $x^y$ (exponentiation),$\sqrt{x}$ (square root).
...
- 688
7
votes
4
answers
2k
views
Make 98 using 6, 7, 8, 9
Try to make 98 using the number 6, 7, 8, 9
Rules:
Allowed operations are: +, -, *, /, ^
Must use all numbers exactly once
Brackets are allowed (but not as binomial coefficients)
Decimal points and ...
- 3,136
11
votes
1
answer
469
views
Make 8528 using exactly eight sevens
Try to make the number 8528 using the digits 7, 7, 7, 7, 7, 7, 7, 7 (eight 7).
Rules:
Use all eight 7s exactly once.
Allowed operations: $+,−,\times,\div$,$x^y$ (exponentiation),$\sqrt{x}$ (square ...
- 13.1k
10
votes
6
answers
3k
views
Make 2026 using digits: 2, 0, 2, 5
Try to make the number 2026 using the digits 2, 0, 2, 5.
Rules:
Use all four digits exactly once.
Allowed operations: $+,−,\times,\div,!$ (factorial),$!!$ (double factorial),$!!!$(triple factorial),$...
- 688
17
votes
2
answers
892
views
Cross-arithmetic
Each white square should be filled with a digit or one of these operators: +, -, ×, ÷. The numbers in the gray triangles indicate the result of evaluating their corresponding expressions.
A minus sign ...
- 531
9
votes
2
answers
742
views
Four primes potion - make 3527 from 2, 3, 5 and 7
Please try my tricky number problem, to create the prime number 3527.
Use all the first four primes 2, 3, 5, 7 in this order, once and only once.
Allowed input manipulation:
Concatenation, decimals, ...
- 16.3k
-4
votes
1
answer
281
views
2025 challenge math worksheet [duplicate]
Use the digits 2,0,2,5 exactly one time each along with any mathematical symbol or operation of your choosing to create expressions equivalent to the numbers between 1 and 20.
3
votes
1
answer
5k
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Make numbers 1-100 using 2,0,2,5
This isn't from any ongoing contest AFAIK.You do not have to have a solution for all 1-100 to post an answer. Partial answers are perfectly acceptable.Similar question for 2024Similar question for ...
- 3,017