maths.
simple dividing, multiplying (speed dist time) etc, understand how sine, cosine and tan work. how to read grahs, curves ect (maths relations, lowest number, relations ratios etc), Vectors it also helps to be able to move equasions around.
Physics.
Simple Gas Laws, Electricity(fair bit inc AC), Forces (Vectors again)
Hope it helps. to be fair, I was pretty crud at all of that, especially maffs, still got through, would have just made things easyer.