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Percentages are reversible. 8% of 25 is the same as 25% of 8, and often one of them is much easier to do in your head.

It's obvious if you think about it, sure.

@ben @fribbledom I sort of knew that but never realized the implications?

@fribbledom this feels familiar like forgotten knowledge.

@fribbledom

This is excellent news

@fribbledom Wtf, never quite really realized it. I must've known but not this obvious. :D

@fribbledom @memethesis interpret % as an arithmetic operator

const % = 0.01

set mono

@memethesis @fakefred @fribbledom Why is the modulo math in my code suddenly not working!

@fribbledom 2nd grade knowledge. Why would you even post something so basic?

because sometimes people overlook the basic ideas.

Please follow my secondary account @fribbledom_advanced_math where we discuss the Standard Model and the Callan-Symanzik equation 😄

On a more serious note: yes it's obvious if you think about it, but just look at all the replies and you'll realize why I post it.

@LukeAlmighty Wow mate I can't believe some people actually didn't realize this.... like lol what idiots dude, these are the exact types of people that fall for email phishing attacks and lose access to their WoW accounts like the kids they are.

@relsqui @fribbledom

Wow... I have seen many things before. I understand there are people who get a very poor education (and one toot about multiplication won't solve that), but to see how many people in here are proud of having a miserable education is truly staggering.

But be proud of whatever you want. As long as it doesn't affect your life, I don't care either.

@relsqui @fribbledom Strange. What you postad was prejudiced at best. That is the exact oposite of kindness.

But if you just want to get angry since I stated there is a problem, you will only lead a miserable life. And that helps noone. Does it?

@fribbledom 🤯🤯🤯

@fribbledom holy h*ck that's useful, I never realized...

@fribbledom I've got one which I found out when drawing geometric shapes one day:

If you count up to a number from 1 and down again

1, 2, 3, 4, 5, 6, 7, 6, 5, 4, 3, 2, 1

Then all the numbers add up to the central number².

break it down into a sequence up to middle number:

Tn = n; a = 1

:. Sn = n/2(2a + d(n-1)) = n/2(2 + n - 1) = n + n²/2 - n/2 = n² + n/2

Second one is second half minus middle :. Sn2 = Sn - Tn = n²/2n + n/2 - n = n²/2n - n/2

Adding, we get:

n²/2 + n/2 + n²/2 - n/2 = n²

@restioson @fribbledom Crikey

@BongoBaggins @fribbledom haha ☺

We were just doing this in class. For arithmetic sequences (where the difference between terms is constant), term n = a + d(n-1) where a is first term and d is difference, and sum to n terms is n/2(2a + d(n-1)). So I just applied those. It's fresh cos we just wrote a test on it haha

@BongoBaggins @fribbledom I get it

x²=x*x

so for y=x+1

y²=y*y=((x+1)*y)=(x*y)+y=(x*(x+1))+y=x²+x+y

so each time you want to go from x² to y², you need to add x+y to x²

@fribbledom this is genius how did I not know this already

@fribbledom Oh my god, thank you so much !

Correct!

@fribbledom then, why the frick didn't they teach us that at school? This would have saved me years of bother!!

Thank you for sharing. You have no idea how much this helps!

@fribbledom wow, thats awsome!

@fribbledom Spot the typo. :) That first bit after 18/(18+1) should be 1/(1+1/18) not 1/(1+18).

@fribbledom what the FUCK

@fribbledom !!

That absolutely makes sense and I had absolutely never thought of that.

@Yulran @fribbledom me too, thanks for that information!

@fribbledom NO i did NOT know that?!

@funnypanja @fribbledom no. 2 is 8% of 25 because of my decision. Everything else was my stupid neighbors to blame.

@fribbledom you mean a*b=b*a or (a/100)*b=a*b/100 .. it sounds very boring stated that way.

I think this makes it a bit more readable:

a% of b = (a/100) * b = 0.01 * a * b

equals

b% of a = (b/100) * a = 0.01 * b * a

so 25 * 8 = 200 and 8 * 25 = 200, and 200 * 0.01 = 2.

therefore

25 percent of 8 is 2

and

8 percent of 25 is 2

right?

Exactly. I don't know why it would be news that 8*5 is the same as 5*8 and just move the decimal place to make sense. People do this all day when out shopping don't they.

@fribbledom I feel so sad that this has to be stated.

@fribbledom@mastodon.social I did a bunch of math to check but holy shit thanks

Ben Lubar@ben@lubar.me@fribbledom % is a mathematical constant equal to 0.01