Subnetting

How complex are the questions on subnetting for the Server 2012 MCSA? How thoroughly do I have to know it? I haven't taken any networking certifications yet, so this is the first exam where I'll actually be having to learn it. For example, are the sample questions from this site: subnettingquestions.com - Free Subnetting Questions and Answers Randomly Generated Online on par with what I'll be getting on the test?
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