Glen Alleman posted on the difficulty (or otherwise) of the maths in EVM, and several of us commented. He followed that with an example in which the maths is very simple, which I quite liked as an introduction to Earned Value.
Marcin Niebudek wrote an article, in which he adds a budget line to an agile burn chart, measuring both in percentages. Nice to see I’m not the only one doing that. (Even if he does draw the chart up the “wrong” way ;-)