Khan's lectures are a bit extemporaneous in an attempt to be more conversational. Because of this, he often makes errors or explains topics sloppily.
It's not so egregious that it ruins the content, and it seems to fit his approach of fun, approachable lectures that will lead the student to explore the topic further with classmates, instructors, other internet resources.
Also, I wasn't to fond of using black background and bright colored squigly writing for learning calculus. I have ADHD and learning math and calculus has been such a huge challenge. But I found work done by patrickjmt[1] to be amazing. It's clear neat and concise, and was able to get through Single and Multivariable thanks to him. My girlfriend and my sister really loved the way he explained calculus as well.
care to explain as I'm confused?