I wouldn't worry about it.
I mean how hard are percentages? To work out a % of another number just divide small by big and times by 100.
eg: 100 divided by 200 is 0.5. times by 100 is 50. 50%. obviously it'll be harder in the exam.
Or adding percent just times by 1. whatever you need.
i.e for 10% increase times a number by 1.1
17 increase is times by 1.17
erm shapes and circles will probably come up. remember to know the REASON for it, not just the angles.
So that's tanjants 90* angles, alternate segment theorm, double angles in centre when subtended by the same arc, equal arcs, that sort of thing.
you'll be fine.