Hey,
Welcome to Australia (and ATARNotes)

Are you doing year 11 general maths or year 12?
If you’re doing year 11 you won’t really need any extra questions - most of them are made for year 12.
Checkpoints are a book that are made for lots of different subjects. They’re a collection of questions from past exams that are sorted into topics. The past exams are available for free from VCAA’s website, however they are not sorted by topic.
I don’t really have any recommendations for specific books that will help as I haven’t got any myself but there’s two types you can get.
1. Summary books - these are just notes and sometimes there are basic questions included.
2. Question books. Many different brands make these, checkpoints is one of these types of books. They are a collection of questions, sometimes original, sometimes from past exams, and they are normally sorted by topic.
If you are in year 11 your textbook should be fine and you shouldn’t need to buy any of these extra resources. If you are looking for more questions or a topic explained differently then you could try a different brand of textbook. Your school may have some, or you may be able to find them at a library.