When you use a PDF, you are forced to grab scratch paper and a pen. You write out the binary. You draw the lines between the network and host portions. This physical act is critical for long-term memory. Apps do the drawing for you; a PDF forces you to do the heavy lifting.
: A direct PDF providing a series of questions on binary conversion and CIDR notation (e.g., /29), followed by a complete answer key. IP Addressing and Subnetting Workbook ip subnetting exercises and solutions pdf better