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The attacks on Khan here personally irked me.

I grew up in a small rural town where math teachers were rare and good ones were nonexistent. I still remember watching Sal Khan's videos on calculus after struggling to get any grip on it from my frustratingly uninterested teacher who was forced into the position after our actual teacher retired. After I saw them I came back with a fire in me because for the first time he exposed me to the beauty of calculus.

This guy is completely wrong about Khan not inspiring students to care. Sometimes all students need is to see what caring looks like to ignite it in themselves. You can feel how much he cares just by watching him because the video is the product of all that caring, and he does it for millions of people.

But thank you to this blog author for being brave enough to call out Khan's failures, I am sure it'll help education much more than Khan did.

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Yes, exactly. I have also learned a lot of math, grammar, science, and other subjects from Sal. In most videos, Sal explicitly states to pause the video and try out the problem before he works through it. I do think that KA's style of teaching needs some getting used to (this was never a problem for me as it was one of my first teaching platforms). However, once you get used to it, it is a wonderful experience.
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Khan Academy is a treasure, and is how I re-learned math in my 20s after not taking it seriously in school. Then moved on to MitX for science [re]fam.

I am having my kids learn math with Kahn academy if we don't have anything better by that point.

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Side note, but much as I like Khan Academy overall, I've always struggled with Sal's slow and repetitive speaking style in the videos.

"Now you add the five ... [pause] ... add the five ... add the five to the seven ... to the seven..."

Running them at 1.5 - 2x helps a bit, but it's still annoying to the point that I find it very distracting.

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While it depends entirely on personal opinion, I believe that it helps significantly. It helps build up the problem/solution from the ground up and he goes through each step out loud to help a student understand. I get that some people hate it and think it is so childish for such simple steps. For other people, it helps a lot. Learning on KA works best if started aat a young age and done consistently (you get used to the style and you learn everything from the ground up).
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YMMV but I found the style very helpful
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In my case, it's not so much that I find it childish, it's that I find it incredibly distracting which means I can't focus as easily on the content. Instead of "oh, now I understand how that equation works" I catch myself thinking "why is he repeating the same word over and over - that's so annoying!". Then my brain starts obsessing over "when is he going to do it again?", even though I don't want it to. It's a bit like trying to deliberately ignore something. It becomes all you can think about.
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OTOH creating neural connections takes time. It's a real distance. Small for us, but great for the cells. That's why explaining difficult concepts too fast, while cool for people getting things instantly, is not good for general population.
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I very much agree and it saddens me often when I see folks dial it up to 1.5x or 2x "because it is boring otherwise". They might think they just get as much, only in half the time, but I'd hypothesize that they retain less because the mind needs some time to digest.

Similar with the trend to auto-cut pauses that speakers make, just to cram in more text into a youtube video. Destroys not just the pacing but any chance for the mind to take its time.

I'd love to see studies about this.

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When I’m understimulated by a teacher, my mind wanders. I’ll start thinking about something else entirely. When my mind comes back, I’ll have missed a couple minutes of content. I can overcome this with willpower, but doing so is exhausting.

Playing videos at 1.5-2x fixes the problem entirely. My attention is held without any effort.

If a concept is new or difficult enough, I just slow the video back down or pause it whenever I need to think things through.

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I don't think you can make blanket statements. Consider:

1. Teacher 1 speaks at 100 words per minute.

2. Teacher 2 speaks at 50 words per minute, for the exact same content as Teacher 1.

You're not really losing anything by playing Teacher 1 at normal speed vs Teacher 2 at 2x speed. For every learner, there will be an optimal teaching speed for a given topic. This may mean listening to some audio at normal speed, some at higher speeds, and some even at slower speeds. I always customise my playback speed to the specific content I'm trying to learn.

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It's not about the rate of speaking but rather about what is actually being spoken. I am currently going through the Neetcode DSA course and it's just obnoxious. His video on Union Find, a 15 LoC algorithm, is 20 minutes.
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There's a difference between pacing (good), and repetitive speech (bad). Between pacing and repetitive speech.
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Ironically, spaced repetition is the key to successful learning.

Obviously one can overdo it. And there is variance in what people require. But not giving things time, instead giving in to the dopamine-craving, that's killing your learning abilities.

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Repeating a sentence twice in a row during an explanation, is not spaced repetition at all. Spaced repetition means testing recall at increasing intervals, usually starting 1 day apart.

"Paris is the capital of France. Paris is the capital of France" -> not spaced repetition.

"Paris is the capital of France. [one day later]. What is the capital of France? [three days later] What is the capital of France?" -> spaced repetition.

And in fact, it's this plus practice where the real value lies in learning and memorising. The only purpose of an explanation from a teacher is to help you understand the concept. Generally once you understand it once, you don't need to understand it again - unless you forget, and that's where the practice / spaced repetition comes in. That's why I prefer the teaching part to be as efficient as possible, so I can focus my limited time on the parts that will make me internalise it.

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It might be annoying if you already know the content. Frame it for the least common denominator (pun intended) - the person who has the time and needs the repetition to pick up a concept.
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I originally learned linear algebra from Gilbert Strang's OCW videos, and I was only able to stick with them by 2x'ing the playback rate; at this point, hearing Strang at his normal speaking rate sounds to me like hearing him after a Robitussin bender.
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I wish YouTube let you increase the speed of videos past 2x. I play almost everything at 2x now, and I have no problem comprehending videos at that speed. I’d like to try 2.5x or 3x but the ui doesn’t have that option.
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There's a bunch of different chrome extensions that do this, and you can do it yourself from the Chrome console with `$0.playbackRate = 3` or whatever.
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This is exactly what my kid said about why he doesn’t like Kahn academy.
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What would you recommend over khan academy?
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I've not tried it myself, but I consistently hear good things about Math Academy. It uses a knowledge graph so that it knows whether you've satisfied prerequisites for a topic, and it adapts itself to your level. I've never taken the plunge because it's very expensive at $49 a month, but it seems to be the one that serious maths learners use.

I did the trial of Brilliant the other day. You can get 7 days free, then another 7 days added if you cancel the first trial before the end. After that you can continue to get 2 free lessons per day with ads. I think it's about $20 a month for unlimited lessons. The maths problems are more visual (which makes them quite intuitive) and it has a nicer, more polished UI than Khan Academy. It's easier to stay in the mood for doing more lessons. The main downsides compared to Khan are that the explanations are quite minimal (short descriptions, no videos), and it doesn't reach as advanced a level as Khan. I'm looking at it as more a way to do a refresher on the maths I already learned at school rather than a serious learning tool. If it were $5 a month I'd probably consider subbing for a couple of months and trying to blitz through all the material before switching back to Khan to fill in the gaps.

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While I am a strong supporter of KA, I just use regular schooling to review and back up what I learned on Khan.
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I don't agree and the hype surrounding his efforts was something much greater than what KahnAcademy actually is (a very useful resource).

He sold his vision in "The One World Schoolhouse" which was essentially global learning via all the best videos (and one unified curriculum) you can make and teachers effectively being technicians/teaching assistants. It was the vision that utopian minded technologists craved in the early aughts.

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It's not a bad idea in concept, but the core problem is what he delivered was:

"essentially global learning via all the Khan videos, in math, by him, and in other subjects, by his team."

Khan Academy is 2010-era state-of-the-art for rote learning and procedural knowledge. That's a helpful resource, but as one world schoolhouse, there is:

- No room for creativity, or much of anything similar from students (outside of the fantastic JavaScript projects).

- No room for outside innovation.

- A personality cult. Any ideas MUST be attributed to Khan.

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Creativity isn't learning, it's the application of learning, and that's not what school is for. There has always been value in somebody showing you how to apply a math technique and practicing using it to solve problems. It's not creative but it gives us the skills to do useful things in the world - including creative things. Even pure rote learning (such as reciting the periodic table) is useful so you can later draw on that knowledge without interrupting your attention on the higher level thinking (such as creativity!) that you're doing.
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> There has always been value in somebody showing you how to apply a math technique and practicing using it to solve problems.

Only if your goal is to teach people how to solve that particular problem. But it’s not the best way to teach mathematics.

For my money, the best way is problem based. I heard of one math teacher who had a video playing as the students walked in. The video was a weirdly shaped bucket being slowly filled by a hose. Students came in, saw him sitting up the back, got fidgety then someone asked “how long will this take??”. At that, he shot up and said “good question”! And they spent the rest of the class trying to estimate how long it would take for the bucket to be filled. Complete with diversions into flow rate, volume, and so on. He made the students ask the question. Then got the students to try and answer it themselves, helping them work through their own ideas on the board.

That’s beautiful teaching.

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I don't want to tangle myself in a "technically correct" kind of discussion however I'd like to point out that Bloom's taxonomy - a widely used model in pedagogical context - has a level for creative work.

It is the highest level of learning, but still a level of learning.

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The article is indeed uncharitable. Nowhere does the article mention the fact that there are exercises AND that you can explore the website and the different resources in the way you like. You don't even need to watch videos if you don't want to.

You also do not need to linearly follow the topics/videos. You can take a few quizzes from some topic, notice you don't understand something completely yet and instead pick up more trigonometry instead.

I've worked through Khan academy in a way similar to what the author describes as a good flow, but then all within the Khan Academy platform. The platform even allows for discussions and questions.

To me the problem is much more that motivation or a destination is not something that Khan Academy will give you. Then again, so won't most teachers. I much preferred Khan Academy over most of my math teachers, but occasionally I've had teachers who helped me love a subject I barely knew beforehand.

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My understanding is that the idea behind Khanacademy is to switch the classroom -- learn a topic as homework; do the questions in the classroom. That way the teacher can assess (and help) the students.

The other idea is that a student only advances to the next topic once they've mastered the current topic (e.g. by getting 4/5 questions right). The theory behind this is that if you don't understand a concept/topic then it is harder to understand topics that depend on that.

This does mean that students will be at different topics/stages. But because of the structure of the teaching a teacher isn't moving on to a new topic leaving students to fall further and further behind.

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The idea of Mastery Learning seems to resurface every couple decades. I guess because it pretty appealing but requires more per-student customization; there’s always a hope that now, finally, we’ve got the tech to let everyone advance at their own pace.

IDK. Maybe some sort of RAG-on-textbook solution will let us do it.

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The idea is for the students to watch the videos outside of class and this frees up time for the teachers to provide individual help.
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