#maths puzzles

[leibnizstan]

fruit posting

[transamus]

thinking about how often ive brought my sudoku book to an event just 2 have something 2 do and people would go out ov their way to be like "oh sudoku? i could never, i fucking HATE math, im really bad at it too" and i'd have to just be like. c. can you not count to 9.

[letusbloomtogether]

Puzzle Games

a mobile application that can be downloaded for free from the Samsung Store and contains many great games

Enter to Samsung App store to get all these games for free. Here's the link below.

https://bit.ly/3Dqzk4j

[mathani]

Animating polygon-by-polygon previously I realized I can simplify my code and construct a tower with an arbitrary number of polygons. What's the smallest and what's the largest height of a tower?

[daz4i]

man you ever force yourself into basic self care like "blorbo would want me to eat rn. blorbo would be very disappointed if i stayed in bed all day. blorbo would want me to be happy" why did i fixate on a fictional guy who wants people to be well. couldn't i become obsessed with an evil guy who wants me dead?? :/

[unnonexistence]

95% of math brainteasers that go viral are just bad notation and it drives me up the wall

[puppyeared]

Childhood

[thatsbelievable]

[arconinternet]

The Canterbury Puzzles (Book, Henry Dudeney, 1907)

You can read it here. If the Internet Archive is still down, you can also read it on Project Gutenberg here.

Image above is from here (also archived here).

[chongoblog]

Have you heard of the Sum and Product Puzzle, aka the "Impossible Puzzle" because it initially seems like there isn't enough information to go on? I think I have the answer, and I'm mad about it.

I hadn't so I looked it up and here's Wikipedia's summary of it

There's also an explanation, but I didn't look. I wanna figure this out myself.

So let's break it down.

"P does not know X and Y" means that X and Y are not both prime. If they WERE both prime, then P would know the two numbers right away. So if S KNOWS FOR CERTAIN that P doesn't know X and Y, that means that the sum of X and Y can't be made up of two prime numbers. So, for example, the sum can't be 20, since if X and Y are 1 and 19, P would get 19 and be able to easily deduce the values of X and Y.

So we have a bound for the sum here, so we just need to find all numbers that can't possibly be the sum of two primes. I tried to get a good list of all numbers that aren't the sum of two primes through trial and error, but I after I found the first few I just let the OEIS do the rest of the work for me

So our possible sums are: 11, 17, 23, 27, 29, 35, 37, 41, 47, 51, 53, 57, 59, 65, 67, 71, 77, 79, 83, 87, 89, 93, 95, and 97.

Now that doesn't narrow it down a TON, but we can probably do something with this. Now that P knows that these are all of the possible sums, they know FOR CERTAIN what X and Y are. Very interesting. That tells me a lot about the product.

So let's say X is 4 and Y is 7. Then P is 28, and S is 11. Now, other factors of 28 include 2 and 14, which add up to 16 (not on the list), so we could just say that and call it a day, but there's something else that perplexes me. What if P is 24? The factors of 24 are 6x4, 8x3 and 12x2, which give us sums of 10, 11, and 14, and 11 is the only one on the list, so we have new X and Y values for S = 11 that could also apply. And since the S mathematician said he knew what X and Y were upon hearing that P knew, we can safely say S isn't 11, since X&Y could have multiple possibilities.

So, simply put, we need a value of S where there's only one possible P that could work for it. On one hand that still sounds like a LOT of guess and check work, but on the other, I feel like there's a way to find this solution without that.

Doesn't matter. I did the guess and check work anyway, granted it was actually easier when I got to the higher numbers, since most possible factors of P went over the sum of 100, which is one of our limitations. Easiest way to find these unique products is to find the largest prime number (lower than the sum) and use that as one of our two values.

So the conversation goes as such.

S sees that their sum is 17. Knowing that 17 can't be reached as a sum of two primes, S says "P does not know X and Y", which tells P that the sum is one of those numbers we saw up there. P's product is 52, he figures and he only knows two numbers whose sum add up to one of those numbers. So he says "NOW I know the value of X and Y". S hears that and figures that it has to be that one EXACT combination.

X and Y add up to 17 and multiply to make 52 which means that X and Y are 4 and-

...

GOD DAMMIT

[enigmachine]

user enigmachine post something non-shitpost challenge (100% WILL FAIL)

ok but i SWEAR i will post something serious….. definitely not today but someday

[the-witchhunter]

DP x DC ramble: Types of power

Now, in this particular fandom, there’s a tendency to make an OP Danny

That’s a neutral statement, a lot of people just happen to like and post OP Danny

For the most part, not my taste but it can be fun in some contexts, but overpowered Danny isn’t my default

Now, Danny is physically strong. His abilities are combat focused and he can hold his own in a fight. He probably has a little less physical strength than you’d think since he uses gravity nullification to lift heavy things, but it’s impressive regardless. He has a goodly variety of offensive and defensive abilities that make him formidable is a fight

But the strongest characters in DC aren’t necessarily strong in that way

Superman is physically very strong, incredibly powerful, but he’s still nowhere near the level of the actual strongest characters, because their power is a very different type

Like I’m talking reality manipulation, omniscience, abilities that involve power over people’s very souls (and a ghost is a human soul) and where they end up. Psychopomps and some much more. I’m talking about beings that can mold the flesh of humans to remove something like a cancer and repair damage with barely a thought

And they’re mainly held in check by rules, mostly just being polite, sometimes Divine laws

This is a type of power Danny is not equipped to handle

It’s a very different game than Danny is playing. He can physically throw down, he might have an army if it’s Ghost King AU, but this is “can kill you with a literal snap and the snap is just for dramatic effect” territory

Danny is playing high school American football, these characters are playing Professional soccer aka what every other country calls football

It’s a very different game, and if he’s trying to play with them, he’s going to struggle

And that’s fine, he can still be OP and not be playing on the same field as Lucifer, or the Spectre, or various demon lords and so on, because it’s a different kind of power

But just arbitrarily saying he’s more powerful really undersells why they are powerful. Being able to punch good is not the same as a character that can just send him to the afterlife. Someone being able to reshape Danny’s body at their will isn’t going to be concerned about his ecto blasts

A Tuna is a big fish, but the ocean is VAST and DEEP

All this to say you’d have to drastically alter Danny’s actual power set to make him able to compete, otherwise you’re just de-powering the actual strongest characters, which is less impressive since it missed the point of WHY they were strong

Just because you can solve a sheet of math problems doesn’t mean you’re going to be able to ace a three page essay on the poetry of Keats

This has been my thoughts on the matter, be sure to grab a souvenir from the gift shop

Also just going to sneak this in:

Danny should probably be more concerned about magic users

Magic clearly can affect him, just look at the Freak Show incident from season one, that’s not even getting into the reality gauntlet. Now add in the fact that there’s a variety of magic items/artifacts in DC and a slew other of magic uses and occultists that can summon and bind ghosts, spirits, and demons to do their bidding

Danny is firmly in the category of beings that magic specifically deals with, he should probably be a bit more concerned about magic users

[sunnyupsidedown]

Math major Neil is all about problem solving so OF COURSE he called that hit. His whole runaway life was a matter of high risk problem solving. Arranging that hit was child’s play

[statementlou]

hey some very smart people (my babes @captainrayzizuniverse and @goldcrumble) have cracked a 28 Clothing pattern check this out: Drop 1 and Drop 2 came out August and November last year and were both Collection 01 (labeled on the clothing tags); Drop 3 (this July) is Collection 02...

...which suggests a possible pattern of one collection consisting of two drops close together late in the year per year, which feels consistent with teasing items from the next drop in the promo for this recent one; so we would see Drop 4- the second half of Collection 02- in October or November, and then another long wait until the second half of next year for more?

[gayvampyr]

ok so i think i’ve noticed a trend between preferences for types of math and science while talking to other people so i want to try and test out a hypothesis

obviously there are more types of science and math but i want to test the correlation between these specifically

[yourgrantaire]

I bought this book from goodwill for a dollar and a lot of the games are hit or miss but overall I'm enjoying it, but there is a section of mental games (just to be played in your head, no pen or paper), and this one game is so unbelievably hard??

Note that you are supposed to do these entirely in your head, writing nothing down.

I wasn't timing myself because I was working on these while I was falling asleep last night but I think the second one took me over an hour.

1. A certain number leaves a remainder of one when it is divided by 2, 3, 4, 5 or 6 but leaves no remainder when it is divided by 7. What is the smallest possible value of the number?

2. A certain number, when divided by 2, 3, 4, 5, 6, 7, 8, 9 and 10, leaves remainders of 1, 2, 3, 4, 5, 6, 7, 8 and 9 respectively. What is the smallest possible value of the number?

And there are 20 of these questions. Totally worth the dollar, hours of fun (if you are the type of nerd I am)