Three unit bridging courses are available or once you've finished HSC you can start learning the level of mathematics required (I also recommend you do the bridging course).
A lot of science majors don't (all the fun ones do though lol), and some just require maths that's not too hard (stats for life sciences or whatever) and I'm sure you could handle.
High school subjects often correlate with different uni subjects.
So, here is a list of subjects at high school that correlate to subjects at uni:
- high school -> uni
- maths -> maths
- maths -> physics
- physics -> chemistry
- chemistry -> biology
- biology -> history of science