What's the point of writing my mathematics well if I don't get extra marks for it?

Although strictly speaking you get no extra marks for writing out your mathematics clearly and logically, getting into the habit of doing so can help your work in a lot of ways: 1. You can read your work back to yourself easily (e.g. if it's from line-to-line rather than all over the page) 2. It demonstrates to others who may look at your work (e.g. other students, teachers, examiners and your tutor) that you genuinely understand the work, and saves them having to figure out what you are doing 3. You will be less likely to make silly mistakes which could cost you a lot of time (and confidence!) in an exam 4. The marks you get are for what you have written down rather than for what you haven't.