This course is designed to not show you how to do math, but instead to show you why the math works. It's very focused on the proofs of the theorems behind math. If you're doing a math degree (or just love math), then you should enjoy this course, especially when it proves the things skipped over in high school such as the Fundamental Theorem of Calculus (Spoiler Alert: It's kind of disappointing how simple the proof actually is for something so important).
Note that this course is heavily linked to MATH1010 which runs simultaneously. MATH1010 has similar content although it focuses much less on on why the math works. While this course (MATH1210) is considered the hardest introductory math course at UON, the final exam contains content common to MATH1010 and MATH1210, and the MATH1210 marks are scaled up based on the performance of the MATH1210 students. This means that you aren't penalised for taking the "harder" course.
The course prerequisite is a Band 5 in 2 Unit HSC Mathematics or other equivalent merits within the university. It is recommended that you complete Extension 1 Mathematics. Extension 2 Mathematics is not a prerequisite or recommended, so you are fine to take this course if you did not do Extension 2. However, there is a fair bit of overlap with the Extension 2 course, so it is advantageous to do it.