I am so glad you say that you found it difficult because that means im not the only one.
It may sound silly but i havent even done my PPL yet but it just so happens i have a training manual for the aerodynamics and i understand the atmosphere layers, temperature, pressure etc quite easily but when it comes to the pretty complex sums i find myself very confused learning it myself.
Perhaps i shouldnt be too worried as i will be having someone explain it to me when i come round to do it for real.
Just thought i would get ahead of the game by learning some of it whilst waiting for my PPL books to arrive.
Thanks for the assistance
Dave