Knowing how best to take in a subject can be one of the most difficult things to actually learn. However effective the teacher tries to be, they cannot make every child absorb the subject if it doesn’t inspire them. Some folk are better at being given a list of instructions and made to learn each part of a subject by rote. This is especially tue of maths, where you either grasp the point of the exercise and thus learn how to work out the problem, or you sit there for hours just trying to understand the question.
When faced with the written paper on any subject that usually has a practical exam as well, I always found it much easier to have done the practical before sitting the written. This way I could relate the questions to what I actally managed to achieve in the test. It became relevant and fresh in my mind.