Welcome to learntosub.net.
learntosub.net is designed to incrementally teach you the skills needed to understand and quickly solve subnetting problems. learntosub.net requires no binary conversion. You will learn a method that uses properties of binary numbers and rules of subnetting to solve subnetting problems using basic decimal arithmetic.
There are 2 ways to use the site:
You can click on the program tab. This path guides you through the videos and exercises in a sequential fashion. This is probably were you want to start if you lack subnetting confidence.
You can click on the practice tab and complete 4 different types of subnetting practice problems. This is probably appropriate if you already know how to subnet and just want to practice.
The site is free to use, but websites cost money to host, so there are some ads. Feel free to click on a few if you want to help.
It'd also be cool if you subscribed to my youtube channel.