So you need a recommendation letter
Dear student, let me explain why I did not write a recommendation letter for you — and how to increase the probability that I agree to write it next time you ask.
Calculate efficiently
Some students are able to reason properly, and apply the right formula, then fail on the last (and simplest) step: calculating the result. So I wrote a short handout explaining how to calculate properly with an electronic calculator or a spreadsheet.
Generate moodle calculated questions
How to use arbitrary complex calculations in Moodle “calculated” questions to generate similar questions with different sets of variables.