Printed copies of these workbooks are available from your instructor by request. Downloadable PDFs are provided for convenience.
The VLSM workbook should be completed after reading the section on Subnetting (NetAcad: CCNA1: Introduction to Networks: Module 11) but before doing the end-of-module exam. It provides three different approaches to doing variable length subnetting and a ton of practice. This workbook usually takes about three hours to complete.
The ACL workbook should be completed after reading the section on ACLs (NetAcad: CCNA3: Enterprise Networking, Security, and Automation: Module 5) but before doing the end-of-module exam. This workbook provides many examples of ACLs, where best to place ACLs, and examples of named and numbered ACLs, Standard and Extended. This workbook usually take about two hours to complete.
Cisco’s Binary Game helps you learn to do binary to decimal (and decimal to binary) conversion quickly. Try playing for 10 minutes every day.
There is a non-Cisco alternative here. I have noticed an occasional bug with the number 256 (technically not an 8-bit number). Once you’re able to hit a high-score of 8,000 or more you’ve probably mastered the 8-bit conversions.