The way they're currently set up, you see the Courses as a drop-down menu and there's just a lot to look at. First-timers may be confused and intimidated by the sheer number of courses available. I think setting it up so each subject has a block of its own would be helpful, and maybe you'd instead be redirected to each subject's page. 

Restructuring the math courses on the Math page by putting it into layers kind of like having "Kindergarten" / "Early Math Review" on the same layer would help determine where to go instead of scrolling through tons of courses.

There are also the "Get Ready" courses, and having them be in a space between different grades/courses would be helpful in maybe having more people use them.

This might just be a personal thing, but I have never touched a "Get Ready Course" so take this with a grain of salt maybe having an introduction/synopsis as to what Get Ready Courses are alongside the actual grades may get more use out of them so that they (and I'm assuming) prepare you, for the next course.

Having it on a completely different block is odd in the way that people may just stick to grades.

There is also the presence of the "EurekaMath/EngageNY", "Illustrative Mathematics", and "FL B.E.S.T." courses. I'm not quite sure if they were made for the public and a specific organization or just that specific org to use in partnership with Khan Academy, but having it more accessible in the layer method I proposed earlier would help students from those organizations find those courses easier. Though they may have an alternate way to access those courses besides looking for them in the "See all Pre-K 8th-grade" menu.

Having the layers may also help the user base of Khan Academy use those courses, but it may also just confuse them so having something distinct to differentiate why someone may want to use one course over the other would help too.

This mainly boils down to one point, having a kind of roadmap would be so helpful in guiding where someone may want to go. The current https://www.khanacademy.org/math page is just this incredibly long page of courses and it's alright at conveying where you can start from and how to progress at the moment, but it could be so much better and giving them sections would make it more digestible for self-learners too.

Having prerequisite knowledge in a course's block/guiding you to that requisite knowledge for a course like calculus would help you know if you've missed a step in your math journey.

| "Kindergarten" |            | "Early Math Review" |

+ needs to know how to read and write?! something like that
- Kindergarten Topics     - Early Math Review Topics that may be similar.

*indent* | Get Ready For Grade 1 |

| "Grade 1" |                    | "FL B.E.S.T, etc." | (for something something)

+ needs to know how to count numbers or something
- Grade 1 Topics              - some topics that may be similar.

These are just suggestions so please correct me if I put it on the wrong topic. Thank you to everyone involved in the Khan Academy project for all the resources you have publicly and freely available. Y'all have been a blessing on the internet so far.