Questions tagged [calculation-puzzle]

A puzzle that involves numerical calculations, such as multiplication and addition. Use with the [mathematics] tag.

Filter by
Sorted by
Tagged with
-5
votes
0answers
90 views

What Number is missing in circle?

Source: https://www.rondogo.sk/ Correct answer is 2 but why?
-5
votes
3answers
126 views

What is the Result of this icon Equation? [closed]

from:https://www.rondogo.sk/hra I have problem with heart :) A) 19 B) 20 C) 21 D) 22
-2
votes
2answers
108 views

What is the right number to replace and why?

Can anyone help me solve these puzzles? Puzzle from: www.treningmozga.com
4
votes
3answers
868 views

Finding a Kakuro trick

The following screenshot is taken from the Android app Kakuro++ (level 9 riddle 12) And I verified the current status within the app. I managed to solve the puzzle by guessing a 50/50-number and ...
2
votes
1answer
248 views

What number is missing in the pentagon? [closed]

What number is missing in the pentagon? Puzzle from: https://www.rondogo.sk/hra/
1
vote
1answer
92 views

Equal row-products and column-products in a given array [closed]

I don't know if this is the right place to ask this question, but I'm stuck on this and can't figure out how to even proceed. Any hints anyone? Is it possible in a 5 × 5 array of integers for all row ...
1
vote
1answer
121 views

Math riddle puzzle

I stumbled upon this math puzzle over one android app. You need to find the unknown number in the puzzle. 92 = 725 61 = 215 74 = 327 52 = ? According to the author ...
2
votes
3answers
235 views

Reversible number problem

These are the reversible numbers In this example we have an operation that on one side gives the result 6 and turning it gives it 12. Is it possible using reversible numbers and mathematical ...
2
votes
2answers
345 views

Minimum number of questions?

This is an interesting puzzle which I've been racking my brain to solve for some time. I've found different variations of this puzzle but it does not seem like this one has been asked before. Here it ...
3
votes
0answers
237 views

What's the missing number in this 3x4 matrix? [closed]

$$ \begin{matrix} 3 & 3 & 5 & 6 \\ 2 & 3 & 6 & 1 \\ 7 & 6 & 3 & x \\ \end{matrix} $$ This math puzzle is supposed to be solved by middle school ...
3
votes
0answers
250 views

Find a missing number in this 28x21 grid

355|066|677|855|677|081|044|855|355|062|216|677|216|855|224|044|034|046|051|677|355|264|044|046|044|351|886|043 043|044|886|357|886|352|225|357|043|222|993|001|233|968|046|225|062|041|351|886|043|227|...
6
votes
2answers
523 views

Math puzzle: I know the answer, what is the equation? Use all digits 1-9

A few years ago, my child brought a puzzle home from their 6th-grade math teacher. The solution was to use all the numbers $1−9$ only once and make the equation true. Using a spreadsheet, I was able ...
2
votes
1answer
165 views

Fill each blank with a digit 1-9 without any repetition [closed]

Fill the following place holders with digits in the range from 1 to 9. Each digit only appears once and make the equation sum up to 100. _ /_ * _ + _ * _ * _ / _ + _ * _ = 100 Also, what is the ...
-5
votes
1answer
104 views

Number puzzle: 5+3=28 [closed]

Another puzzle to solve! :) $5+3=28$ $3-1=24$ $7+3=?$
-4
votes
1answer
106 views

Clock puzzle - 17:45 + 22:05 = 1510 [closed]

I have designed this clock puzzle for you to solve! $17:45 + 22:05 = 1510$ $20:55 - 17:30 = 35$ $06:40 * 19:20 = ?$
5
votes
1answer
137 views

The digits of the cube of a 3-digit number X

The digits of the cube of a certain 3-digit number X are, from left to right, the square of a 2-digit number, followed by the square of another 2-digit number, followed by one digit. (Everything is ...
0
votes
2answers
91 views

Which number replaces the question mark?

I'm trying to solve puzzles to exercise my brain. I'm stuck on this test, I printed it from Mensa IQ Test, an app on Android store. Can someone help me? Below is the test:
-8
votes
1answer
129 views

Puzzling rectangles [closed]

Can you find two unequal rectangles whose areas add to $5\sqrt5$? No computer solutions please.
15
votes
3answers
982 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 ...
31
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{...
3
votes
1answer
251 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
358 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
154 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 ...
0
votes
1answer
175 views

Puzzle storm to infinity

I have been playing Puzzle Storm on Lichess lately. Essentially it involves solving chess puzzles within a given time limit. Additionally, the player gets a time bonus for a certain number of moves. ...
5
votes
1answer
153 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?
3
votes
0answers
113 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
240 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
252 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
167 views

Puzzle with numbers in rings

Find $x$ in the following shape.
0
votes
2answers
157 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
319 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?
7
votes
2answers
437 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 ...
8
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
503 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: ...
-5
votes
1answer
124 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?
2
votes
5answers
837 views

Can you fill the cells by integers? [duplicate]

Can you fill the cells with integers so that all the equalities must be true?
1
vote
1answer
589 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
401 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
140 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 ...
11
votes
1answer
1k 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
124 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
927 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
179 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
89 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
288 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
217 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
121 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
641 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
2 3 4 5
21