Some are easy, some are hard. VFR/IFR comms are a joke, General Nav is tough, stuff like Air Law/Ops is just brute force fact regurgitation (how many fire extinguishers per pax, vortex spacing etc..). Some require decent maths, some just require you to pull the answers from the CAPs provided, plot distances or extract specific figures from airport plates. They're all a little bit different.