That number should be 65,536. All of the AWS documentation have 65,536 plus it makes sense mathematically so where is 65,024 coming from? Curiously 65,024 = 65,536 – 512. Why is 2 ^ 9 subtracted? Hummm….
That would make sense but in the slides they are not doing that for the /28 mask. Should be the 65536 and 16 or 65024 and 11.
This seems to be a typo. Should be /16 would allow you 65534 usable addresses (65,536 minus broadcast and network address). If you happened to create a VPC subnet for that full /16, then you would be left with 65,531 available addresses.
I’ve just pushed an update to the slide.