I found interactive CIDR visualization tools like https://cidr.xyz/ to be very helpful in understanding the notation.

I also end up using https://gitlab.com/ipcalc/ipcalc a lot, and am definitely planning on similarly making it easier in the terminal to manage and visualize the CIDRs in innernet networks. I'm hoping innernet can become a fun way to learn networking in a safe (and cheap) virtual environment.