Questions tagged [calculation-puzzle]

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

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90 views

What Number is missing in circle?

Source: https://www.rondogo.sk/ Correct answer is 2 but why?
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
108 views

What is the right number to replace and why?

Can anyone help me solve these puzzles? Puzzle from: www.treningmozga.com
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 ...
248 views

What number is missing in the pentagon? [closed]

What number is missing in the pentagon? Puzzle from: https://www.rondogo.sk/hra/
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 ...
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 ...
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 ...
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 ...
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 ...
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|...
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 ...
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 ...
104 views

Number puzzle: 5+3=28 [closed]

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

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

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

Puzzling rectangles [closed]

Can you find two unequal rectangles whose areas add to $5\sqrt5$? No computer solutions please.
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 ...
3k views

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 ...
503 views

I was looking at this short video, and it made me think of a puzzle. Let's say you have this set of equations: ...
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?
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?
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 ...
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, ...
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 ...
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 ...
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 ...
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 ...
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 ...
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 ...
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:
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?
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: ...
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 ...