you can't revise maths as you do rote-learn subjects like biology, agriculture etc. your study for maths should have been accumulated over the course of the year. assuming you have been practising textbook questions for each topic everytime you learn it, you don't have to do anything the day before. thats why i love maths exams. no stress haha. why do you think past papers are 'bad' revision lol, theyre really good for practising time management. personally, i hate doing work at school during class, cause i get hungry, the classroom smells like shit, etc, not a good place to concentrate. i just try to listen to the teacher when we get new topics and then go to the library and teach myself from the textbook.