# Questions tagged [calculation-puzzle]

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

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### Number puzzle i really need help with

I found this puzzle in a VRChat world. Its a 6 number puzzle, and I need to know the value of “? ? ? ? ? ?”. I also need to know the number.
393 views

### Living in prime years

A human was born somewhere in interval of [1;1920] A.D. They lived exactly 100 years. They lived through more years that were prime numbers than any other human (of the same lifespan) who was born in ...
119 views

### I found this puzzle in vrchat [closed]

its the number puzzle where i dont know what really is hapenning but i see odd numbers are changing
4k views

### Men digging holes

Suppose 9 men take 9 hours to dig 9 holes in the ground. (a) How many hours would it take 3 men to dig 3 holes? (b) How many men would it take to dig 54 holes in 54 hours?
136 views

### Guess the missing digits [duplicate]

Can you guess the missing digits in the following multiplication? ??? x 3? = ???? Digits from 1 to 9 appear exactly once each. The goal is to solve it with as little calculation as possible.
2k views

### How to solve Rubik's Cube using mathematical formulas? [closed]

I am trying to solve Rubik's Cube, but it took one month for me when I started. Are there any mathematical formulas, rules and tips for solving Rubik's Cube in less time (i.e. minutes)?
166 views

### Visual calculation puzzle

Below are some objects and numbers. Try figure out what they represent and finally replace the question mark.
223 views

### Why do I celebrate later? (still 13,37 years)

A very little time ago, just a bit ago one may say, people started partying. Some even went out of their houses to do so… crazy thing, IMHO. Anyway, I don't, I'll start partying in 4886 days.¹ Why do ...
2k views

### $\tau$ is greatest! $\tau$ is all (from 1 to 20)

(This is basically an extension of $\pi$ Day puzzle one to twenty) $\tau$ is greater than $\pi$ and $\tau>\pi$. Create the numbers from $1$ to $20$ using only: Tau ($\tau$, equivalent to $2\pi$) ...
196 views

### Ten, nine, eight, seven, six, five, four, three, two, one

Some of us already did, and some of us are going to end the years with the word "teen" in it soon, for another 94 years. So let me ask the question: How many distinct numbers can you produce with ...
51k views

### A camel transporting bananas

A somewhat well-known puzzle is described as such: You have a pile of 3,000 bananas. You wish to transport them to a place 1,000 miles away on the back of a camel; however, the camel can only carry ...
391 views

### Four dice puzzle: What's the best throw?

This continues Damiano's puzzle "Four dice puzzle: 2,2,4,5" Damiano keeps throwing his four dice. After a lot of throwing and thinking and working, he has determined for every throw $a,b,c,d$ of his ...
666 views

### Four dice puzzle: 2,2,4,5

Damiano has thrown four dice and the numbers 2, 2, 4, 5 showed up on top. Damiano asks himself: What is the smallest positive integer that cannot be generated with these four numbers according to ...
13k views

### Making π from 1 2 3 4 5 6 7 8 9

There have been two other questions here and here that are similar to this one, but this changes the rules up a little. Your job is to approximate $\pi$ using the sequence of digits (in order): 1 2 ...
602 views

### What's the missing number?

$\begin{array}{ccc}6&7&4\\ 4&11&14\\ 13&2&11\\ 6&8&1\\ 15&3&?\end{array}$ Own attempt at building a puzzle, find the missing number.
233 views

### Maximizing Product of Selected Cards

Jennifer is playing a game. The Ace through King of spades are taken from a standard playing deck and laid out facedown on the table. At any time, Jennifer can select two cards and reveal them, and ...
213 views

### Two cards which product is not a square

There are 100 cards on a table numbered 1,2,...,100. What is the maximum number of cards, which can be selected such that no two cards have a product, which is a perfect square? Example: you cannot ...
85 views

### Date from 2 wooden cube puzzle [duplicate]

In an interview the interviewer asked me a question based on date. Suppose in a office, at the manager's desk there are 2 wooden cubes to show the date of month, every day the manager sets the cubes ...
208 views

### “When the Romans counted the entirety of their whole army, their sum was greater than the value of this.” [closed]

I came across this site and you all seem really smart so I was possibly hoping you could help me. I have this puzzle and I can't work it out, does anyone has a clue or answer? When the Romans ...
5k views

### A New Math Operation?

Your quirky Math teacher comes with a new Math operation called "@" and wants to see if you can figure out what it does. She writes the following examples on the blackboard: 8@5 = 31340 9@3 =...
474 views

### What is the next sequence of numbers?

Seven and seven is forty-two, Eight and nine are fifty; Ten and eleven are sixty-two, And twelve and twelve are five. What is the next sequence of numbers?
10k views

### 4 Attempts to Guess a Number Between 1-15

Is there a way to find a number between 1-15 in 4 attempts? In each attempt you can guess a range / combination of numbers and you will get an answer if the number is in that range / combination or ...
128 views

### A four digit long password [closed]

Mary has a password-protected smartphone, but she is not very good at remembering numbers. She decided to come up with a simple mnemonic, "My favorite things are MILK and EGGS." Her password is 4-...
429 views

### Locked Door Number Puzzle

I'm supposed to make a delivery to a crazed botanist. In case you're curious, the shipping manifest is: ...
692 views

### Number Sequence Series-Question 7

This is a series of questions that are created by me. Here is question 7: (23)，(55)，(155)，(1255)，？，？，(56139611) I will give a hint to you guys in one month if nobody can solve it.
158 views

### Missing Number Picture Puzzle

This is is logical reasoning puzzle in which your challenge is to find the relationship among the given numbers and then find the value of the missing number. Source: https://www.funwithpuzzles.com/...
2k views

### I want an exact value of Pi

Use 1, 2, 2, 2 (Each number used exactly once) to form π. I want an exact value of π, not any approximation. Available operators: + - * / ( ) ^ ! You can use any one of them for any times. Hint:...
601 views

### How to make the number 49?

You've to start with $1$ and can use each of the following operations at most once. You can do the following in any order you like: 1) Add $2$. 2) Add $3$. 3) Add $5$. 4) Multiply $2.$ 5) ...
192 views

### Is there any pattern involved in the following sequence? [closed]

Consider the numerical sequence $$800,1600,4800,6400,12000,6400, \cdots.$$ Is there any pattern involved in this sequence? I am very curious to know that. This puzzle is from a FlipKart Daily Quiz. ...
93 views

### How to fill up the numbers in a set of empty discs drawing a pentagon?

The following pentagon is composed by $10$ discs. Each disc must be filled with one number. The allowed numbers to be used are the first $10$ even positive numbers. The sum of the numbers to be placed ...
132 views

### “Short” And Sweet Math

In the following chess diagram, how many possible chess postions exist? No looking at the solution! Source: P1359129 & Andrew Jonathan Mestel, Retros mailing list, 2/1/2019
183 views

### Find the hidden message in this weird array

This puzzle is from my best friend. ? ? 0 ? ? ? ? ? 1 3 0 1 8 2 0 Figure out the answer. Do not ignore any of the tags! Hint:
93 views

### One-digit products in a row of numbers, base-N

Generalizing One-digit products in a row of numbers to base-N: For which bases N does there exist at least one solution to the following: "The digits from 1 to N can be arranged in a row, such that ...
741 views

### One-digit products in a row of numbers

The digits from 1 to 9 can be arranged in a row, such that any two neighbouring digits in this row is the product of two one-digit numbers. Arrangement: Is it possible to do such an arrangement ...
150k views

### 1 2 3 4 5 6 7 8 9 = 100

The sequence of numbers $1\ 2\ 3\ 4\ 5\ 6\ 7\ 8\ 9$ has the property that you can insert mathematical operators in between the numbers from $1$ to $9$ and make the expression evaluate to 100. For ...
85 views

### Missing number in a 5x5 table

I'm trying to find a solution for the following puzzle. A friend sent it to me and I know that he didn't create it and that's about it for the original source; I tried to find it on the net but I ...
142 views

### How do I answer this?

So, I'm trying to figure out this weird code that was sent from one of my friends. Could someone please tell me the sentence within? 30 30 31 31 30 30 30 30 20 30 30 31 31 30 31 30 31 20 30 30 31 31 ...
273 views

### Magic Race between Rabbit and Turtle - who will win?

The race is for 500km and these are the following items they can use in the magic race... Every defect will activate again after completing the mentioned time. Rabbit has the following items ...
123 views

### A boy who has red hairs [duplicate]

Two math teachers were having a chat: Do you have children? Yes, I have 3 sons. What are their ages? Let's make this more fun. If you multiply the ages of my sons, you get the number 36. Ok. And the ...
11k views

### clock values using just “9” (and some operators)

Sometimes a clock is posted on Facebook and the likes where digits are substituted by mathematical expressions. A friend of mine asked me what is the smallest numbers of "nine" which let one express ...
260 views

181 views

### I need a solution for this puzzle [closed]

This is meant to be a simple puzzle Given that: 3 - 4= -1 5 + 3= 7 2 + 6= 15 30 / 6= 20 Find: 20% of the sum for the final answer Hint: Final Answer Format: 00/0=0 (/ = ÷) (Divide Symbol)
322 views

### Cloudy with a chance of meatballs

I discovered that I can control the local weather, depending on what color shirt and hat I wear at a given location. My home country of Flanmanistan has hired me to go back and do drought and famine ...
266 views

### How to solve the input output puzzle?

Here's the puzzle I am solving daily input-output challenge questions in the gradeup android app in order to take preparation for SBI (State Bank of India) PO (Probationary officer). Here I came ...
415 views

### Somebody hacked my calculator

Harvey the hacker struck again. After powering on my calculator, I entered the Keystrokes in the order shown below. Instead of the Expected Result, I got the Hacked Result. What will be the last ...
5k views

### You surely don't want to score 100/100

The Story: Today, the Maths quizzes are handed out by the teacher. You got 100/100. Everyone got 100/100. But you're not happy with it. Everyone's not happy with it. You want to ...
198 views

### Next term of the series

Find the next term of the series $79,95,25,39,99,$____ $(1)$ $117$ $(2)$ $81$ $(3)$ $243$ Source: IBPS PO mains exam in India
201 views

### Four coins on my desk

I have four coins, all of which are United States currency, on my desk. Some of these coins are face up, and the rest are face down. I know the following facts about the four coins: 1) Each of the ...