Learn lots of maths fast

Hi, I'm doing additional maths at school and we only have 1 hour of it a week so it's been a pretty speedy course so far (I'm in year 11 and we've been doing it since September) and early next week I have my additional maths mock. At my school you have to take a-level maths if you want to take a-level physics, and I really want to do physics but not maths so I've struck a deal where if I do well on the add-maths mock I don't have to do a-level maths. However I really don't feel ready for the mock as we've been taught pretty hard maths very quickly and also I have not been revising (whoops lol). Does anyone have any ideas as to how I can learn enough in a short space of time to get a decent grade? Thank you!!