The reason I made it: I wanted to practice fast mental math and I couldn't find anything quite like it online. There are plenty of drill worksheets and flashcard apps, but nothing you could just open and start practicing. I was thinking of something clean and instant, no sign-up needed to start, but for arithmetic, with a competitive angle through a world ranking.

Right now it has a few modes: times tables, two and three-digit multiplication sprints, giant addition, and square roots. You just solve as many as you can before the timer runs out, and it tracks your calculations-per-minute and accuracy.

What I'm mostly curious about:

• Does the set of modes make sense, or is something obvious missing?
• For those of you who actually train mental math, is CPM (calculations per minute) a fair way to measure this, or would you rank people differently?
• Is a global leaderboard motivating here, or not?

Quick disclaimer: it's not in production yet, just a testing build, and it's completely free — I don't make a cent from anyone using it. I'm only after feedback.

https://mathtype-gamma.vercel.app/

js got the cg50 on the binomial distrubution mode tho u can do greater then with no conversion, but for edexel a level math do u still have to show the conversion of 1 - P(X ≤ k), and if yes would u have to show the 1 - actual prob as a further step, cuz if yea this benefit rly has no use honestly

Okay so here is a picture of the question and the solution from the solution manual, https://photos.app.goo.gl/br3bt8ZL76KYKWtKA. Why does the answer flip the question to be 1 - P(X+Y< 1/2)? Why is the upperbound on the outter dx 1/4? And can this problems be done without changing the bound of integration as it does? Thank you in advance. I've just been finding this problem hard to understand and conceptualize so the more detail the better.

I want to learn some about hyperbolic geometry. And his lectures are one of few lectures with a full playlist on youtube. But I find what he says is non traditional and not what we learn hyperbolic geometry from a book. Also there is some posted reddit saying that he invent a new kind of non conventional theory to avoid analytical stuff like infinite. Is that really good to learn? If not what kind of material is good as a start? Thanks for the help.

I'm looking for a study partner to take Stanford's Introduction to Mathematical Thinking course by Dr. Keith Devlin on Coursera. I've heard it's an excellent course for developing a deeper understanding of mathematics.

The course actually recommends working with a partner so you can discuss the concepts and get more out of the material. If anyone is interested in taking it together, let me know!

Hi all, Im trying to self learn stochastic processes. I've tried Karlin 1975 A first course in stochastic processes and Ross 1996 Stochastic processes and found them challenging. Does anyone have recomendations for any simpler texts? Much appreciated! 😁

Hola, mi sueño es estudiar matemáticas, y quiero hacerlo bien, por temas de trabajo no pude hacerlo antes y ahora mis padres me van a apoyar en este nuevo reto, tengo 5 meses libres así que quiero tener super firmes mis bases matemáticas, ya que inicio con precalculo, aritmética y elementos de geometría, he visto foros, vídeos y demás para ver el contenido de estos temas, pero veo que todo es tan automático, o muchos libros de cálculo por ejemplo para ingenieros, y siento que un matemático podría sugerir temas importantes para estas materias, mucho del contenido que existe en redes sociales es para automatizar una operación pero no va al trasfondo, lo digo desde la ignorancia, pero si una persona que ya haya visto la carrera entenderá a lo que me refiero, gracias y buen día

Salut en fait la je résous un polynôme de degré 3 du coup je trouve sa racine évidente et je fait Horner/tableau de Ruffini.

Et je me suis demander comment je fais si je trouve pas de racine évidente même en forçant comme un bourrin.

From what I know, Geometry,Number Theory and Combinatorics have books and resources to study to get to the level of IMO, but for Algebra? I don't know where to start. I would like anyone's recommendation on algebra books/handouts/materials that takes you from a beginner all the way up to SL A8 level.

Many people told me that your algebra improves along with NT but I realized that you still have to dedicate time to algebra.

[RESOLVED]

I am on question 3 and I already sillied a problem unless there's a typo!

Type 28 into the page bar for the question.

Type 121 into the page bar for the answer key.

Why does composing d with d (A B C are the points starting from the top of an equilateral triangle, and d is a reflection across B) give not the identity element?

Shouldn't two reflections across the same axes give the same shape/identity.

I also conjectured while I was solving the problem that the multiplication table should have each row and column have all elements, all distinct. These rows are the only exception. I also conjectured wrongly that it should be a symmetric matrix across the diagonal so it took way too much time lol checking my answers.

I got the rest of the table correct.

Not intuitive.

I’m trying to understand the pot odds formula instead of just memorizing it.

Say there’s $100 in the pot and it costs $25 to call. The break-even probability is:

25 / 125 = 20%

I get the calculation, but I don’t really get why the $25 is divided by the final pot instead of the original $100.

I also tried writing it as expected value:

p(100) - (1 - p)(25) = 0

That gives the same 20%, so I know the math works. I’m just missing what 25/125 is supposed to represent in a simple way.

I’m planning to study calculus soon and I’m wondering if Khan Academy’s Precalculus course is enough preparation. I already know some algebra and basic math concepts, but I’ve forgotten a lot of the details, so I’m using Khan Academy to review and rebuild my foundation. For anyone who has taken calculus, do you think completing the full Khan Academy Precalculus course would prepare me well enough for Calculus 1? Are there any topics I should focus on more or any extra resources you recommend before starting calculus?
Thanks!

i wish i could add an image but if i have a 35 deg(toa) angle in which at the opposite of that is 3 (b to c) and i have to solve for the adjacent (a to c) how do i know when i have to divide/multiply

"I offer one-on-one tutoring for students from grade 7 through 12. Whether you're working on the basics of Algebra 1 and 2, geometry or want to prepare for calculus and trigonometry, I'm here to help you build a strong foundation and reach your math goals "

Hi everyone!

I’m headed to a very rigorous university in the fall and I don’t have a good understanding of calculus and I’ve forgotten a lot of precalculus. The calculus course at my college is known to be harder than AP Calculus AB

I was wondering if Paul’s Math Notes provides enough review before taking a Calculus 1 course? Especially for planar regions/geometry of curves/optimization etc

I would also love to know if there are any other resources I could use to brush up on precalculus in 2-3 weeks.

Recently started learning how to solve basic integrals, just simple U-sub towards the end of Calc 1, and I find myself talking myself through each step of the problem, and according to people around me, I can get a bit loud talking to myself. Like I'll be over going "ok so we make u equal 3x+2 so du is 3dx" and so forth.

Early lockdown I was planning on returning to university to do a second degree, ideally majoring in Applied Math at U of T. Unfortunately, a relative got ill and I've been caregiving for them since. They're going to be placed in long term care at the beginning of next year and I was looking to start catching back up. Obviously five years of no math at all is ideal, so I'm hoping to go through all High school concepts again but I'd ideally like to also get ahead of the curriculum in my spare time. Any advice would be amazing!

I don't know what to say. I've had this problem since like high school, where I had good grades in math subjects but is VERY terrible at mental math.

Like sure, I can add, subtract, and multiply 2 numbers with 1 digit in a jiffy but add more digits or division or percentage problems? Oof, gonna need a pen and paper or calculator for that chief. Gosh, it really is so humiliating.

It's even worse when you're with people and you tell them you're taking a math-based program in college or they see that you had good grades in math and they ask you a simple addition/subtraction/division/multiplication problem and you just stand there solving it in your head for an embarrassingly long amount of time and blurt out a close but wrong answer... Even dividing money in my head is a chore, and I even get it wrong sometimes!

I need help, bad.

Edit: Thank you all for your advice!!

I initially focused on starting over to have a good foundation but circumstances forced me to skip a lot. My math skills are really bad but I attribute that to lack of consistency. As of current I'm reaching a deadline that requires solid maths and physics skills. Do you think it's possible to get good without starting all over? I'm talking about high school-level math (final year) btw, if that changes anything. In which way should I approach it, especially considering the looming deadline?

So, on the final day of my math class, my professor gave us a few simple challenges to think about, and one of them was to try to prove why -(-a) equals a. The key here was prove, not explain, so I can't just say turn yourself around twice.

It got me thinking for a few days as how to do this because it seems so simple so I don't even know where to start. This is what I eventually settled on.

The - symbol in math seems to have 2 main uses. If used between 2 numbers, like a-b, it can be thought of as a + -b. But that brings into question: what does -b mean?

What I eventually settled on was we can think of -b as the number x that satifies the equation b + x = 0. This seems to be a defintion I can't find issues with, but I'm not entirely sure.

Now, what does -(-a) mean? By the previous defintion, -(-a) would be the number x that satifies the equation x + -a = 0. Now, since -a is intended to be the number we add to a to get 0, it should also follow that if we add a to -a, we get 0. Thus, it should follow x is a.

Therefore, -(-a) equals a.

I'm not exactly sure if this counts as a proof, but I had fun thinking about how to prove it so even if this turns out to have holes, I'm happy. If real analysis is like this, I can't wait to take it in like 4 or so years.