Questions tagged [calculation-puzzle]
A puzzle that involves numerical calculations, such as multiplication and addition. Use with the [mathematics] tag.
998
questions
-7
votes
1answer
74 views
Puzzling rectangles [closed]
Can you find two unequal rectangles whose areas add to $5\sqrt5$?
No computer solutions please.
10
votes
3answers
611 views
A Perfect Diamond of Numbers
A diamond of numbers is an arrangement of circles in the shape of a trapezoid (see figure) in which the number in any circle above its central (longest) row is the sum of the two numbers in the ...
30
votes
2answers
3k views
Sum of the first 86 square roots
Without using a calculator or a computer, can you compute the sum of square roots of the first 86 natural numbers, rounded to the nearest integer? In other words, we are looking for $\sqrt{1} + \sqrt{...
-2
votes
0answers
111 views
Can a relativistic rocket ever dilate time enough to be practical? [migrated]
It seems the best shot for humans to visit other stars is a relativistic rocket, such as the hypothetical 1g rocket, which would dilate time in order for the mission to be completed in the crew's ...
4
votes
1answer
198 views
Six single-digit numbers surrounding a three digit number - what's the rule?
Source: SOF World IMO Class 9
Find the missing number, if the same rule is followed in all the three figures.
2 1 4 2 3 3 4 6 7
\ | / \ | / \ | /
693 374 ?
/ | \ / | \ /...
9
votes
2answers
349 views
Climbing scoring puzzle inspired by today's olympic event
Necessary information. The sport climbing consists of three disciplines: speed climbing, bouldering, and lead climbing. In combined events, the disciplines come in this order, and the combined score ...
-2
votes
2answers
139 views
How to solve this problem on overlapping?
In cases of problems involving order and ranking where there are two indices (namely left and right) there is a particular chance of overlapping. Let us take an example to justify this:
Ranjan is ...
5
votes
1answer
137 views
Sum and product of 9 digits
Adding single digits 1 to 9, the result is 45 and their product is 362880.
Are there any other 9 single digits with sum 45 and product 362880?
4
votes
0answers
111 views
Expected waiting time [closed]
You arrive at a station at time t=0. Train A can come anytime between [0,5] and train B can come anytime between [0,7] and train C can come anytime between [0,9]. You will board the first train you ...
-1
votes
1answer
225 views
Grandfather and Grandson
My Puzzle is as follows-
Once, I said to my friend that, "In 1932 I was as old as the last two digits of my birth year. When I mentioned this interesting coincidence to my grandfather, he ...
-1
votes
1answer
202 views
What's a general method to solve this calculation puzzle?
I need help to work out how to solve this puzzle. The puzzle is very self-explanatory...
2
votes
1answer
161 views
2
votes
2answers
133 views
Find out the odd one in the diagram
I'm solving puzzle from the book super excellent and intellegent test. Im stuck on these. Someone said answer should be 983. But how? Can anyone tell me the right answer. thanks.
0
votes
1answer
151 views
what number should replace the question mark in hexagon diagram? [closed]
I'm trying to solve this problem from a book, but can't understand how it works. Why is 12 in the center? What should be the missing number?
8
votes
2answers
423 views
Is $\sqrt1*\sqrt2*\dots*\sqrt n$ ever an integer?
Is $\sqrt1*\sqrt2*\dots*\sqrt n$ ever an integer?
Note: Deusovi has already given a nice and simple answer. I still wish to welcome more answers as I want to see if there are other ways to approach ...
10
votes
2answers
1k views
Spending 1374.00 US dollars in three days
Jenny received 1374.00 US dollars which she has to spend all or a portion of within 3 days, with the following conditions.
The percentage (of her current dollars) which she is allowed to spend each ...
11
votes
2answers
492 views
Adding rows of blanks
I was looking at this short video, and it made me think of a puzzle.
Let's say you have this set of equations:
...
-4
votes
1answer
116 views
Equation 60 divide by 2 [closed]
This puzzle is from YouTube
60 / 2(10+5) = ?
The answer mentioned is 450. The same answer is shown by Google. But, I believe the answer is 2.
Is the answer 2 or 450?
3
votes
5answers
830 views
Can you fill the cells by integers? [duplicate]
Can you fill the cells with integers so that all the equalities must be true?
2
votes
1answer
144 views
Make 1-100 using 2 0 2 2
You may use the following:
Addition [e.g. 2+2]
Subtraction [e.g. 2-2]
Multiplication [e.g. 2x2]
Division [e.g. 2/2]
Decimal point [e.g. 2+.2]
Exponents [e.g. 22] {tetration is NOT allowed}
Square ...
2
votes
5answers
398 views
Largest pair of consecutive numbers, not greater than a million, that can be expressed with four fours [closed]
What is the largest pair of consecutive numbers, not greater than a million, each of which can be expressed using precisely four fours and an assortment of standard operators (including concatenation, ...
-2
votes
1answer
138 views
How old are Jim and John? [closed]
(Disclaimer: I remember a puzzle like this I did a long time ago, but this isn't a direct copy of the puzzle, only it's formatting. If this is appears to be a copy of another riddle, I will simply say ...
10
votes
1answer
990 views
My grandfather's coins
When my grandfather died, he left his fine collection of coins, not more than 2500 of them, to his children, a different number to each of them, and in decreasing amounts according to their ages.
To ...
13
votes
3answers
2k views
What is the age of the old man?
In autumn of the year 2003 an old man was asked about his age.
He answered: "I was born on a Sunday morning in summer and I celebrated my seventh birthday
on a Sunday morning too!"
How old ...
0
votes
1answer
122 views
Work to time ratio! [closed]
Once Valera left the house, walked to the villa, painted 11 fence boards there, and returned home
2 hours after leaving. Another day, Valera went to the villa with Olga, together they painted 8
fence ...
8
votes
5answers
1k views
Split 1 through 6 into a product of 24 and sum of 12
How many ways are there to split the numbers 1, 2, 3, 4, 5, and 6 into two groups, such that the product of the numbers in one group is 24 and the sum of the numbers in the other group is 12? An ...
10
votes
3answers
921 views
Calculation Sudoku
Here is a new quiz from my daily quiz calendar. I'm trying to find a way to solve it.
The numbers 1-6 should be filled in. And like a sudoku, each row and each column should contain each number ...
-4
votes
1answer
171 views
Not a music rebus
What is the 6-letter word that associates with this rebus?
Helpness Meter 1:
Helpness Meter 2:
Helpness Meter 3:
2
votes
1answer
87 views
Find the pattern of the following series: 7 × 3 = 5? [closed]
I recently came across a certain question which I was not able to solve.
It was as follows:
7 × 3 = 5
9 × 5 = 41
15 × 11 = ??
Can you tell me the logic behind this?
4
votes
1answer
281 views
Multiplying English numbers is strange too
It seems that the English-speaking people multiply the numbers in the very same way that the Portuguese add them: while the latter say that 2+2=8, the former claim that 2×2 is 8:
...
3
votes
2answers
207 views
Pirates dividing booty around a circular table
A group of pirates have plundered one of his majesty's cargo ships and they all carried as much gold coins as each one could find. When they get back to their ship, they sit at a round table and pass ...
-4
votes
1answer
120 views
A Clear, Simple, Geometry Problem [closed]
Draw a shape consisting of all the points equidistant from a specific point. Furthermore, draw a segment passing through a side of the shape exactly twice, and draw another segment so that it also ...
8
votes
3answers
621 views
Calculation - the hard way
This is a puzzle I love to play with my math students and I hope you will enjoy it too:
You are given the numbers 1, 2, 3, 4, and 5 exactly once.
Your target is a number, e.g. 36. Can you create a ...
1
vote
1answer
103 views
Reverse Engineer Chess Software Calculations
TLDR Just the Puzzle
Given a number n and a weight w the function f will result in a weighted number r as follows.
f(n, w) = r
n can be a number from 0 to 200
w can be a number from -100 to 100 (...
15
votes
6answers
2k views
Does this equation make sense?
"The two sides of this equation appear to be different, don't they?" asked Grandpa
I looked at the numbers he had written on a piece of paper and nodded in agreement.
2011 = 1012
"Can ...
6
votes
7answers
1k views
To equip hand sanitizers
There was an event held by a group. In this COVID-19 era, there were many hardships in equipping quarantine supplies, in addition to carrying out the event. Several bottles of the same hand sanitizer ...
10
votes
1answer
422 views
A Cryptic Cryptarithm
An entry in Fortnightly Topic Challenge #48: Unusual tag mix
Solve these puzzles to reveal why I made them.
Matriarch mostly prepared oats for American airline location? (8)
AIRLINE + LOCATION = ?
51 ...
-14
votes
3answers
214 views
In computer science Using the digit 4 exactly four times and 4 signs only and only the operation + is allowed how to get 10? [closed]
in computer science Using the digit 4 exactly four times and 4 signs only and only the operation + is allowed how to get 10?
for example:
$(44 - 4) / 4 = 10$
does not work because 44 is a number ...
6
votes
3answers
577 views
Table of mathematical expressions - fill in 1-9
Fill in the numbers 1 through 9 in the 9 empty cells (each number appears exactly once) to make the row and column expressions equal to the number at the end of the row or column.
Regular math ...
-4
votes
2answers
92 views
A challenge to make 1 - 100 [closed]
So this challenge is you have (don't have to) make the numbers 1 - 100 by using the numbers 1, 3, 4, 6 only once. I'm stuck on how to make 54. Can anyone help me?
P. S. You can use +, -, ÷, x, ! And ...
-4
votes
2answers
107 views
digits in descending order equals 2022
Happy New Year!
Here's a nice puzzle for you guys.
2021 has started and can be written as $$
(-9+8)*7-6*(5-(4+3)^{2+1})+0=2021
$$
Ofcourse many other solutions are possible!
So, the obvious puzzle is:...
1
vote
1answer
153 views
Cut the string!
There are five pieces of blue string on the table with different lengths, the total length of which is 30 cm. There are also five pieces of red string with different lengths, the total length of which ...
4
votes
2answers
244 views
Place 4 players to make 6 distances between pairs
Is it possible to place 4 players on a football field in such a way that the 6 distances between every pair of them are 1, 2, 3, 4, 5, 6 meters?
Source: Moscow Math Olympiad 2001 (Look Inside to Page ...
-2
votes
2answers
91 views
Drawing a line with a ruler [closed]
Imagine we have a ruler on which just numbers 0 and 2 and 5 are marked and the rest numbers are erased. How could we draw a 6 cm line by this ruler?
-3
votes
1answer
154 views
Four rational numbers whose product is 10 and whose sum is 0
It has been shown that every positive integer is the product of four rational numbers whose sum is 0.
Thus:
...
7
votes
1answer
493 views
Long division cryptarithm - KLMN/HIJ = K
The problem statement:
Solve the following long division problem. Each letter represents a unique digit (0-9)
...
2
votes
3answers
102 views
Form a magic square with assorted numbers
Arrange the following numbers in a way such that all rows, columns and the diagonals add up to the same number.
...
-4
votes
1answer
126 views
Use only πs to get e
I am taking this puzzle from inspiration from the Four Fours to get Pi puzzle. The puzzle rules are just slightly different. Here are the rules:
You are trying to get as close to e as possible with ...
0
votes
4answers
244 views
Addition table with hidden digits
Similar to the previous puzzle,
find the values behind the letters.
...
3
votes
2answers
245 views
Yet another mixed sum
An instance of this puzzle is here: https://www.theguardian.com/science/2020/nov/16/can-you-solve-it-the-srcmalbed-nmebur-plzuze
a) It has been swhon taht to raed a txet the oedrr in wihch the ...