Mathematics Stack Exchange
Mathematics Stack Exchange

Questions tagged [recreational-mathematics]

Mathematics done just for fun, often disjoint from typical school mathematics curriculum. Also see the [puzzle] and [contest-math] tags.

Recreational mathematics is a general term for mathematical problems studied for the sake of pure intellectual curiosity, or just for the enjoyment of thinking about mathematics, without necessarily having any practical application or expectation of deep theoretical results.

Recreational mathematics problems are often easy to understand even for people without an extensive mathematical education, even if the theory they lead to may turn out to be surprisingly deep. Thus, recreational mathematics can serve to attract the curiosity of non-mathematicians and to inspire them to develop their mathematical skills further.

Many typical recreational mathematics problems fall into the fields of discrete mathematics (combinatorics, elementary number theory, etc.), probability theory and geometry. Important contributors to recreational mathematics are Sam Loyd and Martin Gardner.

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Graph of infinity

Create a function that plots the $\infty$ symbol when plotted. My function is $$|y|=|\sin x|$$ For $\{x: -3\le x \le 3\}$ Bonus points if your function is NOT mathematically equivalent to mine. Double bonus points if the function is simpler than…
Tobi Alafin
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A question regarding the game of 34

The game of 34 is a two person game using the integers from 1 - 16. Player A selects one of the numbers from 1 - 16. Then player B selects one of the remaining numbers. Players A and B continue to alternate selecting numbers until one of them…
Robert
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Minimum Bits of Information to Identify Flipped Board Square

Somebody sent me a competition Math problem recently (an old one so don't worry about ongoing problems). It goes as follows: You are presented with a 8 × 8 square board, with some of the squares black and some white. You can study the board and when…
gowrath
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Make y the subject of x = y/(y-z)

I'm struggling with this GCSE question, but I think I'm just being silly. I've removed the fraction, making it: x(y-z) = y And then tried removing the brackets, making it: xy-xz = y But I'm not sure how to get all of the y terms onto one side of the…
Jay
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Formula for (word) frequency count

I searched for a mathematical formula for the description of (word) frequency count. Its definition would be: A word frequency count is a measure of the number of times that a word w occurs in some corpus n. I was thinking about something like…
user339319
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What is the area of the shaded region of the rectangle?

what will be the area of the shaded region of the following rectangle. Where 2m*2 and 3m*2 are the areas of the enclosed triangles. I'm trying to figure out any help. thanks
jquery404
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Round to the nearest tenth position

I'm new to this forum, but I wanted to post this question hoping to know if anyone has come across it. Is there a formula in math to round down to the closest power of ten? For example, $n$ : the number, $r$: the round value. if $n = 101\Rightarrow…
Angela F
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Assumption and simple calculation

I'm having an issue with what seems to be an simple question. Here it is: Two hockey teams, team A and team B played a game, Team A beat Team B by 2 goals. The crowd was pleased as there were 8 goals in total for the whole game. What was the game's…
Will
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Taking away pocket money

This is my fist post on Mathematics, so I hope my question isn't too trivial - you won't need a degree to answer this one! - but it's messing with my head.... Allow me to explain..... I'm helping my daughter prepare for her Eleven Plus exam in the…
user313027
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Finding the height of a Building at Night

EDIT: Method $1$ is false, as pointed out by Hetebrij. If it is night, how would one find the height of the building? By assuming I am trying to find the height of a building at night, I am assuming that the building (or anything else) casts no…
S.C.B.
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Ratio of even and odd divisors

I've been given of this problem: Let $r$ be an integer which has $k$ even divisors and $k-3$ odd divisors. Furthemore let $x$ denote sum of all even divisors and $y$ sum of all odd divisors. What are the all possible values of ratio…
Mr. Numbers
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Pinpointing a hidden submarine moving at constant speed

A submarine is moving along the line at a constant speed $s$, starting from position $a$. Thus its position is $a + st$. $t$ does not necessarily start from zero, it starts from some value $k$ that you are also unaware of. Now, at each…
MT_
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Will an umbilic torus intersect itself?

In the below two images you see one with three lines leaving point A each 120 degrees apart and a umbilic torus made from twisting a triangle around a circle. I have tried to construct an umbilic torus with, rather than a triangle, the shape below.…
Joe
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Does this approach to the Collatz Conjecture make any sense.

I was playing around with the Collatz Conjecture and came up with the following: Take any positive integer. If it's odd, multiply by three and add one. If it's even, divide by two. Repeat indefinitely and you'll eventually get one. This is the…
Casey
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Curiosity: Divide by two by inserting number

I noticed that, starting with 0.5 you can divide by 2 twice by inserting a number in the previous result after the decimal point. Specifically, to go from 0.5 to 0.25 a number 2 in inserted after the decimal point and to go from 0.25 to 0.125 a…
Miguel
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