I’m a spatial-visual person, so when presented with this problem as a teenager, I instead solved it spatially. If you stack squares like.
█ ██ ███ … To the hundredth row, you get a shape that is a half filled square that is 100x100. Except the diagonal is fully filled in, so you need to add another 50.
So the answer was 0.5x100x100 + 0.5x100. Easy to visualize, easy to solve. 5050.
There’s a similar problem in sports – I was a teaching assistant for our rural school’s gym class so this one also popped up for me as a teenager. If you have 100 teams and each team needs to play each other team once… You fill in a similar grid, with the teams on both the x and y axis. The diagonal gets removed in this scenario because a team cannot play itself. So the answer is 0.5x100x100 - 0.5x100. 4950. Anyone who has ever tried to plan any sort of tournament can probably solve this intuitively, but 25 years ago I though I was the smartest gym class teaching assistant ever ;)
Asafum@feddit.nl 9 months ago
This is why I never succeeded at math. Like why does this shit work?? How can people just take a problem and be like, nah I’m going to just throw numbers all over the place and reassemble them in all sorts of ways and get an answer somehow…
I can’t just memorize arbitrary nonsense that “just is” I need to know how it works or it never sticks and all the math I’ve ever been taught was just “memorize this arbitrary nonsense and regurgitate a specific formula for a specific application that we’ve spent 0 time explaining other than telling you to memorize it. You want proofs and you can’t get proofs until advanced college courses” well guess I’ll just never understand mathematical manipulation then…
I feel like 50/50 school failed me and I failed at math.
nova_ad_vitum@lemmy.ca 9 months ago
The rules underpinning math are axioms in the end, but they’re not completely arbitrary, because if you change them in most cases it just fucks everything up.
The axioms that were chosen were chosen for good reason, and the rules they result in (such as summation and multiplication being commutative so 3x4=4x3 and 3+4=4+3) allow more complex rules to be created.
There’s a lot of philosophy of math at the core of all this , but it’s not really true that this is all arbitrary.
cucumber_sandwich@lemmy.world 9 months ago
But commutation is not an axiom, is it?
Rediphile@lemmy.ca 9 months ago
It’s not arbitrary. Really try to think about the problem at hand. The ‘why’ is quite apparent. Ask yourself why did they go with 99+1+98+2… in the first place? And why is that the same as 101+101…? What was the benefit of simplifying it to that? How did it save the student time?
You can deduce this yourself and literally no memorization is involved to figure this out. No formulas needed either.
rasensprenger@feddit.de 9 months ago
Once you have the idea, seeing that it works if often easy. But coming up with ideas like that can be really hard, which is why gauss was the only one in his class who got it. There is no general method, you just have to think about stuff for a while, but you can get better with practice. And it feels really good when you prove something for yourself, even if it’s relatively straightforward. You can just try to prove some simple things yourself, if you want, the advanced college courses are just for proving really advanced stuff.
TserriednichThe4th@lemmy.world 9 months ago
Look up how to solve it by george polya
sj_zero 9 months ago
It's just a matter of breaking the problem down Into an easier problem or set of problems.
All the additions are interchangable, so you could choose to add 1+2+3+4 or 4+1+2+3 and then 4+1=5 and 2+3=5 and then youve got 5+5 which is easy its 10. So you go ok you can do the conversion with 1 and 50 except it's still tough mental math so you say 1 and 100 to get 101 100 times, but that's twice too big so you slap it in half and you get the answer. It's solving a tough problem by splitting it into problems that aren't as tough.
The first step is knowing what tools you have in your belt. The second is knowing how they work in detail. The third part is the inspiration of using them in a way that solves a difficult problem.
I'm not a mathematician, but I've found interesting solutions to problems like this before, and it's fun when you understand your tools and understand the problem and it all comes together to find a solution nobody else would have.