• Announcements: Welcome back from the holidays, I hope you were able to get some rest last week! Please remember that HW1 is due today by 11.59pm EDT via Blackboard; and there are no classes this Wednesday once again (as per the Lehman Academic Calendar), so our next classes are on September 20 and 22. As planned in our schedule, they will be pre-recorded, and the next live (on Zoom) class is on September 27. Until then, if you have questions you would like to discuss, please send me an email or drop by on Zoom office hours!

• Video 1: Archimedean property. Download file or watch below

• Video 2: Examples of $\sup$ and $\inf$. Download file or watch below

• Video 3: Rational numbers are dense in the real line. Download file or watch below

• Video 4: Infinities and the extended real line. Download file or watch below