Questions tagged [calculation-puzzle]

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

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70
votes
15answers
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 ...
3
votes
3answers
587 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.
8
votes
1answer
214 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 ...
-5
votes
1answer
63 views

Puzzles related to 1337: Puzzle 1 [closed]

Here's a set of puzzles related to 1337. The first one goes here: One digit for each question mark. $1337=1?×3×37+?$ This is pretty easy. Solve it.
5
votes
1answer
203 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 ...
1
vote
1answer
81 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 ...
0
votes
1answer
201 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 ...
18
votes
8answers
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 =...
6
votes
1answer
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?
15
votes
7answers
9k 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 ...
0
votes
1answer
120 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-...
6
votes
0answers
413 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: ...
4
votes
0answers
683 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.
-2
votes
1answer
146 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/...
4
votes
1answer
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:...
7
votes
4answers
582 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) ...
-1
votes
2answers
190 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. ...
1
vote
2answers
90 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 ...
65
votes
11answers
49k 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 ...
4
votes
1answer
128 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
1
vote
2answers
182 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:
1
vote
1answer
91 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 ...
12
votes
2answers
739 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 ...
44
votes
10answers
148k 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 ...
1
vote
1answer
84 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 ...
2
votes
1answer
141 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 ...
0
votes
1answer
272 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 ...
1
vote
1answer
122 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 ...
2
votes
4answers
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 ...
3
votes
1answer
241 views

Missing Number in a Seven Segment Circle

What number should replace the question mark? Please be helpful. If you have the answer, please reply to this post with the explanation and answer. If you don't have the answer, then don't comment. ...
-2
votes
2answers
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)
10
votes
0answers
318 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 ...
2
votes
1answer
253 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 ...
12
votes
2answers
414 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 ...
18
votes
3answers
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 ...
3
votes
1answer
195 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
2
votes
1answer
199 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 ...
5
votes
2answers
701 views

Legal advise for a family dilemma

"A client of mine," said a lawyer, "was on the point of death when his wife was about to present him with a child. I drew up his will, in which he settled two-thirds of his estate upon his son (if it ...
0
votes
1answer
249 views

Fuzzy's Fizzy Dilemma [closed]

Fuzzy the Fuzzball's friends was going to the Fuzzball Festival, and of course he went along. While there, he saw the most curious display. The booth was displaying brand new types of Fuzz. There was ...
1
vote
2answers
378 views

Off roading in a desert [closed]

You’re off-road, in the desert, driving an all-terrain vehicle. You’re $10$ miles off the straight highway, and your destination is $100$ miles ahead, also $10$ miles off the straight highway. You can ...
8
votes
3answers
5k views

How to make 21?

How do you make $21$ from the numbers $1$, $5$, $6$, and $7$? You can use the operations of addition, subtraction, multiplication and division, as well as brackets. You must use each number exactly ...
11
votes
6answers
2k views

Some interesting calculation puzzle that I made

So I'm creating some kind math puzzle that goes like this: 1=-2+3 12=3*4 123=(4*5)+(6+7)*8-9+10 (thanks JS1 for finding shorter one) 1234=(5*6*7*8)-(9+10+11+12+13+14+15+16+(17*18)+19+20+(-21+22)) ...
2
votes
1answer
136 views

Oops! Mixed up Multiplication - Needs to be Fixed

$Given$: $U$, $V$, $C$ are distinct digits, varying from 1 to 9. $U$ > $V$ > $C$ $UVC$, $VCU$, $CUV$ are concatenated Numbers $(UVC)*(VCU)*(CUV)$ = $234235286$ The digits on the right hand side ...
3
votes
6answers
46k views

Fill number in missing?

Given options are: A. 13 B. 42 C. 18 D. 30
5
votes
3answers
284 views

Find the missing Number?

This is Tricky Puzzle That Will Totally Blow Your Brain. Source with answer: Note: if you answer, do it with an explanation.
1
vote
1answer
91 views

Express the given Fractions as Continued Fractions

Using only the numbers, $1$, $2$, $12$. No concatenations allowed. Only permitted signs are plus and division. Brackets are not needed. Expressions should be as concise as possible. Typical ...
1
vote
1answer
75 views

Figure out this Four digit Palindrome with two distinct digits and

The sum of the digits of the palindrome is Same as the number remaining after last two digits are removed.
10
votes
2answers
1k views

sorting 4 numbers using Min - Max boxes

Min-Max is a box that is capable of determining which of the two numbers is the higher (Max) and which is lower (Min). I need to use minimum amount of boxes in order to sort 4 different numbers (any ...
19
votes
17answers
9k views

Number 88 from the digits 2, 0, 1 and 7?

Can you use the digits 2, 0, 1 and 7 each only once to create the number 88?
2
votes
1answer
104 views

Resolve these Highly Narcissistic Relations

$U$, $V$, $C$ , $D$ , $E$, $F$, $G$, $H$, are distinct digits, varying from 1 to 9. $UVCD$, $EFGHD$, $EHHEV$ are concatenated numbers. Please deduce these with concise reasoning from the given ...