Hacker News Reader

Compared to what? They have a track-record of students not even old enough to be in high school yet passing AP Calculus BC exams.

Here in Taiwan, where I live, it's not that uncommon for people to pay 5x that price per month on supplementary math courses for their kids.

Compared to Kahn Academy, which also has a proven track record, is free, and has been around for a long while.

If your time is worth even $1/hour, the "free" Kahn Academy option will be far more expensive than this program.

I respect what Sal Kahn built, especially in the early days, but it's just not anywhere near as time-efficient.

Is there any data to back that up? Just because it's a paid resource doesn't mean it's better.

The tool might be good but there’s also strong selection bias due to its price.