Questions tagged [expression-building]
For challenges about rearranging a set of mathematical operators or numbers to fulfill a certain expression.
34 questions
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Flip the order of operations
Scientists have made contact with a parallel universe. Just one problem: They write math differently. Help the scientists make a program that can convert normal math expressions to their equivalent in ...
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9
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Cryptic Multiplications
Given two non-negative integers e.g. 27, 96 their multiplication expression would be 27 x 96 = 2592.
If now each digits is ...
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6
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answer
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Represent any integer with an expression that uses no digit besides '4' [closed]
Fourward (Introduction)
I have an unhealthy obsession with the number 4. I love it so much, in fact, that seeing any other digit is frustrating to me. I therefour wish to create a 'Fourier ...
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Golfing Expressions
We can write mathematical expressions using the standard math operators (,),+,...
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8 out of 10 programmers like countdown [duplicate]
Edit (Jan 24/2021): The original specification for the challenge had a few problems. Underneath the original text, I have added alternate conditions that were suggested by @caird-coinheringaahing (...
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Represent n as an expression containing all the digits
Related Challenge: Single Digit Representations of Natural Numbers
Task
Write a program/function that when given a non-negative integer \$n \le 100000\$ outputs an expression which uses all the ...
- 13.7k
7
votes
6
answers
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Build the smallest number
Given a non-empty list of digits 0 though 9, output the smallest number that can be produced by an expression formed by reordering these digits and introducing exponentiation signs ...
- 32.6k
6
votes
2
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2D interpolation
Given required values for an expression with 2 variables, output a short expression which fulfill these values
Input
You may take the input in any reasonable format, e.g. ...
- 10.9k
27
votes
8
answers
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Single Digit Representations of Natural Numbers
Task
Write a program/function that when given a positive integer \$n\$ and a digit \$d\$ which is not 0 outputs a way to represent \$n\$ using only addition, subtraction, multiplication, ...
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3
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Make Three from One [duplicate]
Given a single digit integer and a three digit integer, output a mathematical formula that uses only the single digit and a given list of operators to equal the three digit integer.
Input: A one ...
- 9,588
13
votes
1
answer
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Not just a four fours puzzle
In this variant of the Four fours puzzle your should use up to x x's (and no other number) and a defined set of operations to ...
user9207
20
votes
24
answers
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Make Zero From First 'n' Numbers
Challenge
The challenge is to write a code that takes a positive integer 'n' as an input and displays all the possible ways in which the numbers from 1 - n can be written, with either positive or ...
- 5,350
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votes
8
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Find number of ones to get a number using + and *
Introduction
Your goal is to find the least number of ones you need to add or multiply together to get the input value, this is A005245.
Input
One positive integer N.
Output
The smallest number ...
- 289
15
votes
2
answers
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Mathematical Expression Showdown!
You are given 6 numbers: 5 digits [0-9] and a target number. Your goal is to intersperse operators between the digits to get as close as you can to the target. You have to use each digit exactly once, ...
- 6,686
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votes
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Operator precedence: How wrong can I be?
Say I have an expression:
9 * 8 + 1 - 4
This expression can be interpreted in six different ways, depending on operator precedence:
...
- 15.6k
16
votes
10
answers
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Fewest operations to 100
Overview
Given a list of digits, find the fewest operations to make 100
Input
A string of digits, which may or may not be in numerical order. The order of the digits cannot be changed, however plus ...
- 269
8
votes
1
answer
398
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Roots and operators
I used to play a game while I was in the car, it consisted in taking the n-1 first numbers of another car plate and use operators and roots on them to get the ...
user68509
16
votes
2
answers
525
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Make mathematics with minimal matchsticks
Meta-background
This was set as a question on Puzzling, and the instant reaction was "well, someone will just solve that by computer". There was a debate about just how complex a program to solve ...
user62131
29
votes
10
answers
4k
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Solve an equation with (almost) any numbers you like
Given a string of the characters +=- where there is at least one =, insert positive integers between all the symbols and at the ...
- 90.8k
10
votes
10
answers
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Find operations required to get result
So task is simple, given array of numbers and result, you need to find what operations you need to use on numbers from array , to obtain requested result.
Let's make it simple for start, and allow ...
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16
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8
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Express a number with only 0-9 and the four operations
Explanation
Befunge is a two-dimensional program that uses stacks.
That means, to do 5 + 6, you write 56+, meaning:
...
- 50.6k
26
votes
11
answers
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Official Dyalog APL 2016 Year Game
If you think this could be fun, but too much work, consider participating in this much smaller challenge.
A bit of fun (and possibly frustration!) for 2016... Dyalog's "puzzle of the year". ...
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13
votes
23
answers
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10 9 8 7 6 5 4 3 2 1... Print 2016 [closed]
As a spin-off to my challenge over at Puzzling, your goal is to output 2016.
Rules:
You must include the numbers ...
- 4,565
19
votes
1
answer
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Make a math equation from the date
In my Economics class, my friends and I like to come up with ways to rearrange the digits in the date (in MM/DD/YY) format to create a valid mathematical equation. For the most part, we are allowed to ...
- 7,405
15
votes
1
answer
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Arithmetic... tock... tick... tock
This question brought to you by a game I like to play when stuck in long phone meetings.
Given any two times from a 24 hour clock (from 00:00 to 23:59), how many valid mathematical equations can be ...
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votes
2
answers
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Express a number - a modern "Des Chiffres et des Lettres"
Express a number
Back in the 60s, the French invented the TV game show "Des Chiffres et des Lettres" (Digits & Letters). The goal of the Digits-part of the show was to come as close as you can to ...
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13
votes
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Two-zero-one-five puzzle
Background
This puzzle is a variation on the four fours puzzle (itself the topic of a past question). Like that puzzle, the aim is to find mathematical expressions for different whole numbers, using ...
- 2,999
15
votes
4
answers
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It’s time to do the math
Introduction
This is one of my favorite math puzzles.
Given a digit (say 3) and the number of times to use that digit (say 5), generate 10 expressions which result to 1, 2, 3, 4, 5, 6, 7, 8, 9 and 10 ...
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6
votes
2
answers
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Longest mathematical expression in a grid
Given a grid which contains these signs: 0..9, x, =, write the fastest code that outputs the longest string of connected (horizontally, vertically, and diagonally adjacent), distinct cells which is a ...
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votes
12
answers
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Generate all possible integers
Input: you are given 2 integers, n and k. n is a positive (>= 1) integer, and ...
- 595
24
votes
4
answers
4k
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Four fours puzzle
The Four fours puzzle is a popular recreational mathematical puzzle that involves using exactly four 4s (and no other number) and a defined set of operations to reach every number from 0 to a given ...
- 3,404
11
votes
1
answer
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Generate a number by using a given list of numbers and arithmetic operators
You are given a list of numbers L = [17, 5, 9, 17, 59, 14], a bag of operators O = {+:7, -:3, *:5, /:1} and a number ...
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7
votes
4
answers
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generate a valid equation using specified operators
A twist on a recently asked question, you are given a list of operators and a result and you need to find integers which, when operated on by those operators, generate the result.
Example 1
input
<...
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12
votes
2
answers
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Generate a valid equation using user-specified numbers
This is based on a game one of my math teachers used to play in middle school. He would write 5 random one-digit numbers on the board, and then a random two-digit number. We would try to create an ...
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