Questions tagged [calculation-puzzle]

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

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2
votes
1answer
151 views

Something I loved the most

Below are some puzzles you need to solve to make a 4 letter word. 1. 105 35 315 ? 2. I am the most important element in your surrounding. I was found by a Scottish physician. Who am I? 3. I am ...
3
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2answers
114 views
4
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5answers
591 views

Place the numbers 1-7 in the squares so that each row and columns adds up to the same total

A F B D E C G A+B+C = B+D+E = F+E+G Numbers 1,2,3,4,5,6,7
1
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5answers
406 views

Analogy with Number

The given analogy is 343 : 989 :: x : 669 What is x? 223 332 333 233
2
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1answer
137 views

Find missing number

In below grid there are 2 numbers missing fill it with appropriate number . Text version: 69 10 13 192 ? 45 279 64 ? Hint :
3
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1answer
115 views

Math Puzzle: Totaling up A,B, C [closed]

We know the following about the numbers $a$, $b$ and $c$: $$(a+b)^2=9,\quad(b+c)^2=25, \quad(a+c)^2=81$$ If $a + b + c ≥ 1$, determine the number of possible values for $a + b + c$
5
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1answer
181 views

Find the missing 2 number inside inner circle

This puzzle is made by me. In the below diagram you can see there are two missing numbers; you need to fill them with the appropriate numbers.
3
votes
0answers
186 views

3 x 3 Grid Square Problem

For a question that I need to answer, we have to show that there is only one arrangement for which, in a 3 x 3 grid in which the numbers from 1 to 9 are placed and 5 is the centre number, the sum of ...
-1
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0answers
98 views

Please solve this interesting riddle [closed]

Hi There, Please help in solving this puzzle.... Thank You!
3
votes
1answer
159 views

What is the missing number in this grid composed by 25 values?

Well, I have created a simple table with 25 values, inside it, all the data is readable, except for one that is hidden. Can you guess it? The table:
5
votes
1answer
858 views

How to programmatically solve math puzzle

I have this puzzle and I want to solve by code. I wrote simple code trying to brute force but it fail in one condition https://dotnetfiddle.net/cJyu3w Anyone know of a link or source how to solve ...
6
votes
1answer
111 views

A Tribute to Countdown

Leave empty or put a multiplier, divider, adder or subtractor in the boxes: For example:
6
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2answers
131 views

Squared, what is in the post-scriptum?

Just received an invitation from a fellow mathematician for a party. The invitation is quite clear: where I need to be at what time is clearly said in the invitation, but at the bottom of the ...
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0answers
110 views

Find the missing number in the series

Numbers in the series: 4,12,14,16, ?, 25 Please help me find the missing number in the series above. I have already tried with different sequences but unable to solve this. Thanks.
11
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1answer
428 views

Can you decipher these ancient numerals?

This stone was found at the foot of an ancient door. This old note with some mathematical relationships was discovered nearby. Can you use this information to figure out what number each of the 9 ...
14
votes
1answer
479 views
+50

Shots, shots, shots, shots!

Once in a while I go out for a drink to my favourite bar. Normally is just drink a beer, eat some snacks and have a good time with my three friends. But last night I wanted to do some shots. The ...
7
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1answer
208 views

Picture-Puzzle. Find the number!

Make sense out of this picture below and find the two-digit number! Note: Pay attention to everything except the rounded rectangles
9
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1answer
388 views

Given these numbers, find the hidden word

Given this sorted list of 33 numbers, is it in your power to find the riddle they are hiding and figure out the secret word? ...
3
votes
1answer
529 views

Challenge on ASCII Codes

My friend shared a challenge puzzle with me but I don't have any idea on this? I believe that it's related to ascii characters.
8
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1answer
208 views

Six cities. What's the missing number?

Six cities are listed below. For five of them, their numerical value is given. Find the missing number. $$\text{London = 6800}$$ $$\text{Paris = 9248}$$ $$\text{Seoul = 9100}$$ $$\text{Tokyo = 7500}$$...
6
votes
4answers
1k views

Quick way to find the square root of 123.45654321?

If $n^2= 123.45654321$, then what will be the exact value of $n$? Is there a neat/efficient way to solve this without using the long division method? Since this is a GRE question, I believe there ...
10
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2answers
194 views

Find the missing number from the pyramid

? 1 3 3 3 9 9 3 1 9 Find the missing number in the pyramid?
16
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2answers
653 views

16 number puzzles on a blackboard

I have left you some number puzzles on the blackboard. Solve them and let me know what they spell. Hint:
10
votes
1answer
272 views

Catching the thief before it's too late

London, 17:15. Inspector Arbor wasn't quite happy with the current situation. Normally, he would have enjoyed this sunny Saturday outside at the Park but now wasn't the time for that. Valuable ...
11
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7answers
3k views

How should they divide the money?

Three friends go on a picnic. John brings a loaf of sliced bread. Raj brings sliced tomatoes and Von brings a package of sliced cheese. They make sandwiches and eat them. John’s sandwich has 2 ...
6
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4answers
317 views

9 8 7 6 5 4 3 2 1 = 0 and 1 2 3 4 5 6 7 8 9 = 0

There are many number sequence puzzles on this site. I acknowledge them all. Martin Gardner introduced the puzzle with the 9 digit sequence with math operations, reaching 100 as below An old ...
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5answers
389 views

Multiple XOR operations

Find $8$ distinct $8$-bit numbers, each with $4$ bits set to one, such that the cumulative XOR of these bytes is $10101010$. I imagine there are multiple answers, so the first correct answer wins the ...
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2answers
95 views

Which number is the largest in this division case? [closed]

I came across this puzzling question in a coaching school exercise book for children preparing for selective high school enrolment test. I can't figure out the answer and suspect something was wrong ...
1
vote
1answer
116 views

Banknotes recalling [closed]

Last year the inhabitants of Elfland (which are -of course- Elfs) had a referendum and decided to stop using barter and to adopt their own currency (the Elfcoin). On January 1st, 2020 the central ...
10
votes
1answer
624 views

Three shy fairies performing two thousand times

Three shy fairies participate in a dance competition. Since they are shy they don't want to be seen by anyone except for the five judges of the competition. The competition is composed of $2000$ ...
3
votes
3answers
536 views

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.
7
votes
1answer
422 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 ...
3
votes
1answer
155 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.
2
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1answer
191 views

Visual calculation puzzle

Below are some objects and numbers. Try figure out what they represent and finally replace the question mark.
5
votes
1answer
229 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 ...
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votes
3answers
223 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 ...
8
votes
1answer
248 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
222 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
90 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
211 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 ...
16
votes
7answers
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 ...
-2
votes
1answer
169 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/...
5
votes
0answers
466 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: ...
1
vote
3answers
358 views

3 bags of coins, find which bag contains fake coins, doing only 1 weighing

Probably a very easy puzzle for you guys; my point is more a mathematical one. FYI, it was shown in an episode of Columbo. You have 3 bags of coins. Each bag contains 50 identical coins. Two bags ...
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
647 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
195 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
98 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 ...
4
votes
1answer
135 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
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1answer
97 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 ...

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