/r/funmath

Photograph via snooOG

I happen to like arithmetic, but that's not all math is! I didn't when I was a kid, but that's because I sucked and had some uninspiring teachers. I made this place to post some math I think is inspiring, interesting, or cool.

I'm not actively promoting this, but I often x-post from other subreddits, so that's probably what brought you here.

Feel free to subscribe and post stuff you find interesting as well. If you want to be a mod then message me.

I happen to like arithmetic. I didn't when I was a kid, but that's because I sucked and had some uninspiring teachers. I made this place to post some math I think is inspiring, interesting, or cool.

I'm not actively promoting this, but I often x-post from other subreddits, so that's probably what brought you here.

Feel free to subscribe and post stuff you find interesting as well. If you want to be a mod then message me.

Other Resources:

/r/math

/r/mathpics

/r/MentalMath

practice mental arithmetic

/r/funmath

977 Subscribers

1

A problem given to elementary school children in China

0 Comments
2024/11/30
20:50 UTC

1

What is this integer?

With 1,192 digits, this integer happens to include 8675309, a pop-rock song from 1981!

This integer can be expressed as a simple mathematical operation of two integers, X and Y, which together only have 5 digits. What is it?

0 Comments
2024/11/27
20:42 UTC

1

An interesting geometry problem with a simple solution.

0 Comments
2024/11/25
23:47 UTC

0

Many will miss this !

0 Comments
2024/10/30
02:06 UTC

0

99 Percent cannot solve this !

0 Comments
2024/10/22
20:55 UTC

3

Tricky Math Riddle

0 Comments
2024/10/18
00:24 UTC

1

Can you add fractions (no calculator)?

0 Comments
2024/10/11
19:42 UTC

1

Learn Percentages Fast

0 Comments
2024/10/09
18:02 UTC

2

A fun geometry problem that is not easy.

0 Comments
2024/04/22
21:51 UTC

1

I am an Indie Developer who created a Math Puzzle inspired from Wordle. Do you think I qualify as a Fun Math Puzzle? Please share your feedback ~TIA

0 Comments
2023/10/05
20:21 UTC

4

u cannot be a normal scientist if u did not get it

0 Comments
2023/04/08
22:31 UTC

3

I created a Math game focusing on MDAS. I designed it for kids so you might find it too easy. Any feedback is appreciated.

1 Comment
2023/03/08
18:39 UTC

4

Fun Age Equation

Was thinking of how to find a birth year that would be equal to someone’s age. Ended up with the following.

(100-x)+y = x

Simplified to:

y + 100 = 2x

Where x = last two digits of birth year and age

And y = last two digits of current year

3 Comments
2022/09/07
04:37 UTC

2

A challenge!!!

I tried to post this in psychology but they’re losers and don’t allow text script.

Do you believe if nobody could leave there mark on social media or even other literature or music sport etc. besides country of origin+their initials & birth year, experts would be able to identify who was posting the content bas3d on what was posted?

I’ll help with some basic math

26 characters in alphabet. Initials would have to match up 3 times.+birth year 40m pop Canada. 370k babies are born here a year. No data of new born immigration rate available on general search.

So I can’t remember the formula but I think it’s probably around 200 without putting factors in like “general names” would have the exact same initial + birth year.

Fantasy theoretical fun of the day? :) Take this theory as far as you want maybe say you could track 130 or 20 out of the year and initial :) of course you would need beyond state of the arc military grade nasa gear but w/e let’s say you had it.

0 Comments
2022/08/20
18:25 UTC

3

A kind of pattern in random numbers

Take nearly any number with two or more digits and reverse order those digits to create a mirrored number. If those two numbers are subtracted from each other, the result will always be a multiple of three or nine. Also, the result number's digits will always equal nine when added together (sometimes this step must be repeated once or more until the single digit nine is arrived at). Obviously, any numbers with all like digits are excluded from this as well as those like 141 and 161. A number with any zeros after the first digit like forty would be 40 minus 04 for 36.

A couple of examples,

18, 81 - 18 = 63, 63 ÷ 3 = 21, 63 ÷ 9 = 7, 6 + 3 = 9

1234567, 7654321 - 1234567 = 6419754, 6419754 ÷ 3 = 2139918, 6419754 ÷ 9 = 713306, 6419754 with its digits added together equals 36 which then equals 9

1 Comment
2022/04/09
15:13 UTC

3

My girlfriend, who is studying math at university, is a huge math nerd. It's her birthday in a bit. Any math-related gift ideas would be amazing.

What would you, as someone who likes math, like to receive?

Any cute/inspiring books? Thats pretty much the only math thing I can come up with.

3 Comments
2022/03/16
13:16 UTC

2

New Math YouTube Channel -- Calculated Factoids

3 Comments
2021/07/09
22:46 UTC

1

Angle between two isolated lines?

Two isolated lines (which are price points basically, one unit of time apart, each).

Line 1:

  • Price point 1: 1.1
  • Price point 2: 1.2

Line 2:

  • Price point 1: 1.3
  • Price point 2: 0.7

What is the "Angle" in degrees between both lines? To me this is a simple X/Y Graph where for both 'Price Point 1' is X = 0, and Price Point 2 is X = 1.

arctan(1.2-1.1) - arctan(0.7-1.3) = DISASTER.

Cuuld someone Please provide answer to above in bolded text?

This is not home work I am a grown man who can't math and am facing existential dread what seems basic. Thanks.

2 Comments
2021/03/14
03:22 UTC

2

If cosh(x) is positioned inside x^2 so that they are tangent and do not cross, where do they touch?

6 Comments
2020/12/23
20:14 UTC

4

How tall must a parabola be in order to roll and completely flip over? (Made in Blender 2.91)

https://youtu.be/bsmgvC4Nafo

This question was posed to me by u/Xane256 in a comment to a post I made about rolling parabolas.

I haven't yet worked out the precise height. Still trying to figure out how. But I know it's just a little bit less than 5.4

Oh and please don't hate on me for my poor Blender skills. Literally just started using it today.

1 Comment
2020/12/22
04:25 UTC

6

A rolling parabola as a function of its height

https://i.imgur.com/QhaAknM.png

https://www.geogebra.org/calculator/xtw3c4mh

https://youtu.be/g71oTtWK8SU

I've been on a parabola kick lately. Made this cool applet to show where a parabola would come to a stable resting point as a function of its height. Forgive my inefficient construction of this applet, i'm not a geogebra wiz. If anyone has a way to optimize this kind of thing please let me know i'm trying to get better.

Some fun exercises...

*Easy... Where along the parabola's central axis is the center of mass as a function of its height? (use f(x) = x^2)

**Medium... What's the tallest the parabola can be before the vertex is no longer stable?

***Hard... How tall must the parabola be if you want the flat part of the parabola to rest at a 45 degree angle?

****Extra Hard.... How tall should the parabola be so that the point of contact on the rolling surface is 1 unit from the origin (1,0) (assume non-slip "surface")?

11 Comments
2020/12/14
00:06 UTC

4

ANIMAL CROSSING MATH!!!!!!!!!

I have created a video that looks at the math behind the game Animal Crossing for Nintendo Switch! My using proportional relationships, we can find out how much each item is worth in materials, and use that to find a way to make MORE BELLS FASTER! Check it out! :)

https://youtu.be/06n0uu_6Ug0

1 Comment
2020/05/19
17:13 UTC

6

Indoor fireworks is never a good idea.

0 Comments
2019/09/27
12:15 UTC

2

Wet math

Guys, I have really important question. Suppose I have (n) wet wipes, they are all similar (a*b), with equal thickness (t). How should I fold them to get biggest area with predefined lower limit for thickness? What is the optimal way to fold to get it with minimum number of folds? Is there any known algorithm for this kind of problems?

Thanks)

0 Comments
2019/08/12
12:35 UTC

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