Questions tagged [calculation-puzzle]

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

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8
votes
2answers
658 views

Professor Halfbrain and the next square

Yesterday afternoon I met professor Halfbrain at a coffee place. The professor looked very tired. He told me that he hadn't slept for many days, spending his time with writing lots of zeros and with ...
1
vote
2answers
293 views

Time Traveller Maths

On a Wednesday afternoon, Marty McFly starts his DeLorean at 14:00 hours and travels 30 years in the past. After spending 3 days 30 minutes, travels 60 years to the future where he stays for another ...
3
votes
1answer
645 views

Clock values using only the digit 3

What is the minimal number of 3s required to create a clock where each of the hours is replaced by a mathemetical expression using only the digit 3 and standard mathematical operators? A friend ...
4
votes
2answers
461 views

Lionel Messi's soccer puzzle

Lionel Messi sentimentally remembers a small soccer tournament in which he participated many years ago. There were four teams in the tournamnent: Atleticolino, Barcelino, Chicorrotico and Diminuto. ...
3
votes
1answer
178 views

A Chuck-a-luck variant

You're thinking of trying a variant of Chuck-a-luck. In this variant, you choose one number in the range $1$ to $6$ and five dice are rolled. These are the payouts: ...
5
votes
3answers
647 views

First to Five Points

The Problem: There are two players. Each player writes a number, hidden from the other player. It can be any integer 1 or greater. The players reveal their numbers. Whoever chose the lower number ...
12
votes
3answers
3k views

A new six-sided die

Enrico wants to construct a new six-sided die with the following properties: Each side should show a positive integer Different sides should show different integers If two sides share an edge, then ...
9
votes
1answer
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 ...
8
votes
2answers
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 ...
2
votes
5answers
640 views

Largest number with five 1's and five numeric operations [closed]

You have five 1's at your disposal, together with five arithmetic operations of your choice. However, as you only have five operations, you should choose them wisely. Question: What is the largest ...
6
votes
2answers
606 views

A puzzle about flies and trains

So I have a website with some job interview type questions on it. Yesterday I pulled a question out the depths of my memory: A train enters a station at 50m/s where it starts to decelerate ...
10
votes
4answers
2k views

A sloppy calculation

Little Johnny Red forgot to write the multiplication sign between two 3-digit numbers $x$ and $y$ and simply wrote them as one number. When Johnny's teacher graded the homework, it turned out that the ...
15
votes
1answer
969 views

One beer too many

You're standing outside your apartment building after a late night out, with perhaps one beer too many, and you realize you have completely forgotten the code to get in. Luckily, you're a mathematical ...
4
votes
1answer
479 views

May the fours be with you!

In the picture above, all the numbers 1-12 are given, using only three nines. Now, I want to make a similar watch, but using fours instead of nines. Can you make a list of the numbers 1-12 using ...
2
votes
1answer
412 views

Whose lock is lock-ier?

Two friends, Amy and Ben, each use a three-disk combination lock to secure their bikes. Each disk has $10$ orientations, with integers $0$ to $9$, so there are $10^3$ possible combinations. One day, ...
7
votes
2answers
958 views

What date can it be?

To save money, a meticulous person had a oddly unique way of splurging money. Each day the person would splurge an amount equal to the month-digits + day dollars. So for the first of April it would ...
15
votes
4answers
4k views

For how long did Lisa walk?

Lisa gets picked up from work by her husband at exactly 4 pm every day. One day Lisa finished work half an hour earlier and started walking to meet up with her husband. She met her husband on the way, ...
8
votes
3answers
475 views

Professor Delvershys calculations

After spending half of the night with important calculations Professor Delvershy arrived late this morning. To his dismay he discovered that one of his students used the unexpected spare time to ...
8
votes
2answers
1k views

The Magician's Card Game

A magician by the name of Jason carries a deck of cards with him everywhere he goes. He has a game where you can say any phrase and a specific card will correspond with that phrase. The goal of the ...
32
votes
12answers
4k views

Mr. Hilbert and the Problem of the Erroneous Equation

Having had just checked into the Grand Hotel, Mr. Hilbert slumped into the hotel room armchair with relief. Finally he could have some peace and quiet and solve the quaint riddle his colleague gave ...
4
votes
2answers
552 views

Another Way to Count Sheep At Night in Bed

I came across this puzzle: A wayfarer asks a shepherd how many sheep he has. He replies that if he numbered them two and two, or three and three, or four and four, or five and five, or six and six, ...
18
votes
5answers
3k views

All clock hands at equal degrees from each other

My dad once asked me: At what time will the second hand, minute hand, and hour hand on an analog clock all be $120^{\circ}$ from each other? It's a simple question, but I thought it was a fun ...
15
votes
1answer
930 views

Ernie and the Artificial Emmental

I dropped in on Ernie last week to help him prepare for his annual hosting of the Wine and Cheese Club party. This was a special occasion because the invited guest was the famous oenophile and ...
14
votes
2answers
1k views

All Words Go to Heaven?

In the fantasy world of this puzzle, Heaven has 7 levels (1 to 7), with 7 being God's level. Hell has 8 levels (-1 to -8), with -8 being Satan's level. Purgatory (0) is somewhere in between. Your ...
5
votes
2answers
300 views

Paying an unusual toll to the troll

You approach a bridge and see a troll. He throws down finite $n>0$ bags. Each bag, $B_i$, contain 1 or more of 4 possible buttons. $B_i$ contains $S_i \subseteq \{green, red, blue, yellow\} \land ...
-6
votes
2answers
168 views

mensateaser [level 0] (part 1)

What should be the value of the bottom row in our Euro 2012 Football themed grid?
5
votes
3answers
3k views

Express the number $2015$ using only the digit $2$ twice

Can you use only two instances of the digit $2$, along with the mathematical operations below, to create an expression that evaluates to $2015$? Allowed operations: arithmetic operations: addition ($...
5
votes
3answers
368 views

Monkey on a Flagpole [closed]

A 3 feet tall, hungry monkey is trying a reach a magical banana placed on top of a flagpole. The flagpole is 25 feet in height and is slippery to grasp. Every Odd numbered Jump, the monkey climbs 3 ...
15
votes
2answers
1k views

Ernie and the Unexpectedly Exposed PIN

I dropped in on Ernie a few days ago. As I pushed open the door to his workshop I could hear a clanking, hissing noise and then saw Ernie emerging from a great clouds of steam, his face blackened with ...
8
votes
1answer
557 views

What's Jeremy's Encryption Algorithm?

As a result of their solutions to this puzzle, store owner Jeremy promoted both Cerberus and Quark to top managerial positions. Soon after starting their new roles, they were somewhat surprised when ...
4
votes
4answers
2k views

An Hourglass Puzzle

This puzzle follows from the well known sand timer puzzles: A Sand Timer Challenge http://www.crazyforcode.com/sand-timer-puzzle/ http://www.cut-the-knot.org/hg_solution.shtml Warmup: You are given a ...
11
votes
1answer
1k views

What is a Donut Phrase™?

Bwahaha! You're not the only one who can make these puzzles, JLee! (this is an unofficial continuation of JLee's [in]famous Word/Phrase puzzles) The following phrases of varying lengths follow a ...
3
votes
5answers
574 views

Chile to Singapore

Hey guys, I've been into brainteasers since I was little and recently decided to make a puzzle-related website. I figured that this will be the best place to share some of my problems and see if they ...
2
votes
1answer
204 views

Depressed Numbers [duplicate]

$12 = 0$ $1234 = 1$ $123456 = 2$ $12345678 = 4$ $369 = 2$ $248 = 3$ $2 = 0$ $3 = 0$ $5 = 0$ $7 = 0$ $11 = 0$ $13 = 0$ What does: $123456789 = ?$ Why? Hopefully isn't too hard, please ask if you ...
3
votes
0answers
129 views

Minimum number of telephone calls needed to exchange information [duplicate]

There are 16 secret agents who each know a different piece of secret information. They can telephone each other and exchange all the information they know. After the telephone call, they both know ...
19
votes
5answers
2k views

What is a Surpassing Phrase™?

If a phrase conforms to a certain rule, I call it a Surpassing Phrase™. Use the examples below to find the rule. Some details to save you time: 1. Font doesn't matter. 2. The number of words ...
12
votes
1answer
853 views

Ernie and the Bubbles of Lucretia

"So, what do you know about milking spiders?", asked Ernie as he passed a fresh cup of coffee to me. Good grief!, I thought and gave an involuntary shudder as I glanced at the milk jug sitting ...
8
votes
3answers
2k views

Baumic Numbers!

I have a class of numbers; this class of numbers contains a certain number if and only if it is baumic. The following are baumic numbers: 1, 6, 9, 15, 20, 21, 30, 33, 39, 45, 50, 51, 56, 57, 69, 70,...
5
votes
2answers
9k views

Finding Day Puzzles

When the day after tomorrow becomes yesterday, the day which would then be today will be as far from Sunday as the day which is yesterday when it's two days after that day's tomorrow. What day of the ...
-1
votes
1answer
1k views

Cryptic Woman and a Confused Census-Taker [duplicate]

I recently found a card on which there were two puzzles, both of which have me stumped; I want to spend a little more time on the other puzzle, but here is one that stumps me: no 65 A census-...
7
votes
1answer
633 views

MC Frontalot 80085

MC Frontalot is a musician, and one of his songs is a word problem that seems to me like it belongs here. If you want to listen to it instead of just reading the lyrics, a quick video search of "MC ...
0
votes
3answers
10k views

A Water Jug Problem [duplicate]

Suppose you are given two jugs: a 4-gallon one and 3-gallon one, and neither has any markings on it. You have a pump that can be used to fill the jugs with water. What do you do so that exactly 2 ...
15
votes
3answers
2k views

The Pie-Maker's Son

Preface: There's a lot of background story here. Most of it is just for fun but there are definitely clues sprinkled throughout. If you want the strict puzzle, skip on down to the bottom. For many ...
-4
votes
1answer
861 views

Using the digits 2, 3, 4 make an expression for 30

Write an expression using exactly one 2, exactly one 3, and exactly one 4 to make 30. For each problem, you must use all three of these: Division Factorials (just for regular factorial use, no ...
-5
votes
2answers
1k views

Make 24 and 30 using the digits 3 and 4

First, write an expression using exactly one 3 and exactly one 4 to make 24. Second, write an expression using exactly one 3 and exactly one 4 to make 30. Math You Can Use for each problem: ...
0
votes
3answers
478 views

What happened to the missing £10? [duplicate]

I have come across a puzzle, which makes no sense. Does anyone know the answer to the below? You and two friends go on holiday. When checking out, the total bill comes to £300. You pay the bill ...
7
votes
4answers
2k views

A Threes Of Cake

This question is similar to my other question Twos For Thought, which arguably was a better pun but I decided to recreate the question, except with threes! How many threes do you need to get to the ...
4
votes
4answers
575 views

Twos For Thought

How many twos do you need to get to the number $100$ exactly? Example: $22+22+22+22+2^2+2^2+2^2$ This example method uses 14 twos and is obviously not ideal. Can you find a way that uses the least ...
0
votes
3answers
1k views

Find a number that is 9 times bigger than total of its digits?

Find a number $X$ that is 9 times bigger than the total of its digits: for example if $X=abc$, then $X=9*(a+b+c)$. I don't know the number of digits; it could be 3 or 2 or more.
4
votes
2answers
1k views

Unique Licence Plates

Note: This is a Mathematical puzzle, not a Mathematical problem. Although the answer could be solved with mathematics, lots of problems on Puzzling SE could be solved with mathematics, and the problem ...