Questions tagged [calculation-puzzle]

A puzzle that involves numerical calculations, such as multiplication and addition.

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6
votes
16answers
14k views

How do you get 23 using the numbers 1, 2, 3 and 5?

You can only use Addition, Subtraction, Multiplication, Division. This is for a math project for my daughter. You can only use the numbers once and all numbers do not need to be used.
17
votes
2answers
4k views

Doomsday will occur in the year with a triple blue moon

A group of men are working and counting on a very serious prophecy, which says "Doomsday will occur in the year with a triple blue moon". When will Doomsday occur? Note : A blue moon is a second ...
2
votes
1answer
149 views

Instructing People to use minnimum time for a task? [duplicate]

There are 5 persons standing on a side of tunnel. A, B, C, D, E Each takes 10, 30, 15, 20, 29 minutes to cross tunnel ...
-3
votes
5answers
230 views

Interesting card combinations [closed]

In a normal pack of playing cards (without jokers), the probabilities of the following events are the same: (1) Drawing a set of 4 different cards (irrespective of its color and suit) - let us call ...
3
votes
6answers
3k views

Upside-Down Number Problem

These are numbers that can also be read upside down as the same number, or different number: 0, 1, 6, 8, 9, 10, 11, 16, 18, so on. Each number can only be used once. Using these numbers, try to get ...
-2
votes
3answers
153 views

Redesign an analog clock [closed]

An odd mathematician and engineer decides to redesign an analog clock. It now has 2 periods of 10 hours, each hour is divided ...
4
votes
2answers
448 views

Boggling googling

I'm a number for you to evaluate, Googling 'me' gives the drop off the Empire State, Though the great Google finds no results for me, I'm just a pure integer value you'll see. What number am ...
1
vote
3answers
616 views

What is the next number in the following sequence?

1, 6, 5, 3, 4, 1, 2, 2, ? Hint: the task is pattern recognition using basic mathematical operations.
4
votes
2answers
656 views

mystery operations

1.  3 __ 2 __ 36 __ 4  =  67 2.  3 __ 2 __ 36 __ 4  =  150 3.  3 __ 2 __ 36 __ 4  =  176 4.  3 __ 2 __ 36 __ 4  =  71 Fill in the blanks ...
9
votes
1answer
458 views

Arrange numbers into the quadrilaterals

Arrange numbers 1 to 14 to the quadrilaterals, such that: The difference between 2 numbers in squares having a common edge or corner is greater than 2. Numbers inside the green quadrilaterals are ...
4
votes
3answers
2k views

Gumball Machine Logic Math Puzzle

You walk into an antique shop and find an unusual gumball machine. On the back of the gumball machine you can set and lock five dials with the following labels: Percentage (0% through 100%) Pink (0 ...
2
votes
1answer
217 views

Generate a valid string

I have been observing her for just over a week now. She had seen me but didn't know she was being watched. As people pass she hands them a piece of paper. Some even stop and put money in a cigar box ...
0
votes
1answer
251 views

Help with this puzzle?

Here is a set of problems that I encountered during an examination. Can anybody help me find the numbers where the '??' symbols are? $\begin{bmatrix}10&6&2\\15&31&?? \\15&96&7 ...
14
votes
4answers
3k views

Mother and Daughter

A mother (not yet a centenarian) and her daughter (who happens to share her mother's birthday) are both a prime number of years old. Moreover, in their lifetimes there have been at least a dozen other ...
15
votes
2answers
2k views

What am I worth as a TART?

I hope it's not too easy. As CAKE I'm worth 573,566. As PIE I'm worth 33,062. What am I worth as a TART? Note : It's not a word game.
5
votes
5answers
506 views

Move a number's position to get the right equation

$62-5+3*2=25$ Move a number's position in order to get the right equation.
2
votes
2answers
308 views

Macbook air falls off x floors and survives! [duplicate]

You've just bought an anti-shock skin for your macbook air and want to make a review video for your vlog showing how good it is at absorbing shocks. The skin has a special property that either ...
7
votes
2answers
2k views

Prime sums in a 4 x 4 board

Place the integers 1 to 16 in the sixteen cells of a 4 x 4 board so that the sum of any four numbers in a row or column is a different prime.
5
votes
1answer
554 views

Rolling a dice - Expectation Question [closed]

I heard / read / acquired this puzzle from somewhere: Roll a die, win $2\times$ the value of the face if it is an even number, or win $1\times$ the value of the face if it is an odd number. How ...
-2
votes
2answers
185 views

Doubles and Trebles [closed]

There are two ponds having lotus flowers - pond A and pond B. The property of the flowers of pond A is such that they get doubled (that is twice) in number every day as compared to previous day (6:00 ...
3
votes
2answers
234 views

Everything leads to “one” number

You get an invitation from an Institute of Mathematics and you are told if you can solve a simple puzzle you can be part of their elite institution. You have to fill the blank. $6 \rightarrow 6$, ...
4
votes
2answers
534 views

Man selling sheep

A man with 90 sheep wants to sell them in a market 30km away from his farm. He went searching for trucks to load his sheep and he found out that every truck can carry 30 sheep at a time, but he will ...
4
votes
3answers
4k views

Solving a Rullo Puzzle

How can I solve in a (relatively easy) way, a Rullo puzzle? (Screenshot below) Rules: Enable or disable a circular number (pink is enabled) in order to make the row or column match the sum on the ...
10
votes
2answers
571 views

What is a Scheming Word™?

In the spirit of the What is a Word™/Phrase™ series started by JLee, a special brand of Phrase™ and Word™ puzzles. If a word conforms to a special rule, I call it a Scheming Word™. Use the examples ...
2
votes
3answers
219 views

Menu subset puzzle creation help

I'm having trouble finding out the best way to create the lists of numbers for the puzzle I'm creating. There are 2 sets of 13 integers (from 1 to 50 inclusive). Call these $A$ and $B$. There exists ...
0
votes
2answers
2k views

Arrange to get sum of 450 when it is added row wise and column wise

I just came across a maths puzzle,where i should get the sum of 9 numbers(multiples of 10) to be 450 both horizontally and vertically in a 9x9 matrix. Picture attached for reference:
5
votes
5answers
2k views

Sum of rows and columns.

In the puzzle, each square is to contain a digit from one to nine. No digit can appear twice in the same row or column. The sums of each row and column are given. Find one of the two solutions. In ...
11
votes
2answers
761 views

Mike's Coin Duplicator

This is my first mathematical puzzle on the site. To be honest, I don't know if this should go to M.SE or here. Any grammatical or backstory edits are welcome, as I realized that my English is not ...
1
vote
2answers
187 views

Monkey with Coins Killing [duplicate]

10 people can share a bucket of coins equally. A monkey steals one coin. The number of coins remaining is therefore 1 less than would allow them to be shared out equally. One person after another ...
2
votes
1answer
342 views

Find the Cell Number, free the Mayor

Last night, the mayor of a small town was kidnapped. 2000 suspects have been brought into the local prison based off eyewitness reports as to what the suspect looked like.One of these 2000 suspects is ...
9
votes
1answer
1k views

What is the rule these numbers follow?

Each row in this grid of numbers follows a specific pattern or rule: ...
3
votes
8answers
965 views

An exercise on the powers without using the logarithm function

One can find on the forums a lot of exercise where the pupils call for help to solve their maths, once I came across an exercise similar to this one: Determine with a simple (non-scientific) ...
2
votes
1answer
193 views

Gambling problem [closed]

I have a Gambling problem. One night I go out and get to a casino and do the usual, get my regular at the bar for only $10 tonight at the bar and head over to the tables, I hit a bit of a bad luck ...
9
votes
2answers
805 views

Simple set of equations

Find 4 equations of the form A [OPERATION] B = C, using the numbers 1-4 and operations $+,-,\times,\div$. Each number must be used once for the A's, once for the B'...
1
vote
3answers
734 views

Math number puzzle/riddle

This not-so-simple puzzle asked by my teacher today, given: $2+2=3$ $4+8=27$ $3+4=8$ So, the answer for: $5+32=?$ I'm new here so pardon my mistakes. Please let me know what you guys thinks ...
5
votes
4answers
676 views

Sticks and stones may break my sum

13 sticks and two stones are laid out as follows: Move three items so the arrangement makes sense. Only the basic functions ×÷-+= are allowed.
1
vote
1answer
158 views

Simple probability game [closed]

You are asked to play a classic shell game with two shells. Each round, a ball is placed under one shell, the shells are rapidly, continuously rearranged for 15 seconds with distraction*, and then ...
3
votes
6answers
45k views

Fill number in missing?

Given options are: A. 13 B. 42 C. 18 D. 30
-7
votes
2answers
767 views

Find the missing number : [closed]

Find the missing number in the following table. Answer Options are: 25 27 32 30
-11
votes
1answer
1k views

find the missing number in the following table

Find the missing number in the following table. Answer Options: 10 12 15 16
3
votes
1answer
575 views

Can you find the pattern?

If the following are true: $4+7+2 = 281435$ $7+3+9 = 212781$ $6+2+7 = 121456$ $2+8+5 = 164036$ Then what would the following equal? $8+4+6\ =\ ?$ Can anybody check my work? I ...
11
votes
2answers
1k views

Lets see how smart Puzzling' stack users really are!

Let's see how smart Puzzling stack users really are! Try to solve the value of x (get angle value). This is related to the http://thinkzone.wlonk.com/MathFun/Triangle.htm , you can search online how ...
1
vote
0answers
53 views

Total number of squares + inside square [duplicate]

How to calculate total number of squares if n×n square box available. Need to calculate 1×1, 2×2 up to n.
5
votes
1answer
280 views

Try to find the hidden letters!

Try to find the hidden letters! Tips: ▲ 1: (1/2)π^2 2: (2πr) + 2r 3: (2πr) + 4r
7
votes
2answers
857 views

Getting to the Root of the Problem

TD:LR - Only the equations and bold question at the bottom are part of the puzzle; the rest is just flufftext. After a long time of searching for the origin of the device I previously posted about, I ...
19
votes
5answers
6k views

How to get 5 from 0,0,0 and 1?

Can you use the digits 0,0,0 and 1 each only once in a mathematical expression for the number 5 using only common mathematical symbols with at least 1 mathematical symbol between each number?
2
votes
4answers
550 views

All locked up and nowhere to turn

While working in your basement, you notice there is a portion of concrete which is not like the rest. It is funny you never noticed it before, but most of the time there was a rug covering it. Tapping ...
9
votes
2answers
366 views

Looking for another partition of 100

The sum of ten, not necessarily different, positive integers is 100. If placed adequately on the vertices of this graph, two of them will be joined by a line if, and only if, they have a common ...
19
votes
11answers
5k views

Add parentheses to make this true

Add parentheses to the following to make a true equation: $10-9\times8-7\times6-5\times4-3\times2-2\times1=1$
3
votes
2answers
434 views

Solve This 'Unknown Operator' Problem

Source If below equations are true, 24 % 6 = 64 35 % 5 = 87 63 % 7 = 99 Then based on similar logic what's the value of below equation ...