"Oxford Mathematics for the New Century 2A" is a standard textbook, so it does not contain a specific "interesting essay" as a standard answer.

Use the resources available to understand the process , not just the result. If you master polynomials and linear equations in 2A, you are setting yourself up for success all the way to the HKDSE.

For some geometry proofs or algebraic manipulations, the guide occasionally presents two valid methods — which builds flexibility in thinking.

When you finally close your 2A textbook, having genuinely mastered indices, factorization, linear equations, and deductive geometry, you will realise the most important answer was never in the back of the book—it was in your own growing ability to think critically about numbers and shapes.

The answer key might require 3 significant figures, while you provided 2. 3. Work Backward