Choosing the best college for studying Mathematics at Oxford depends on several factors, including your academic focus, social preferences, and financial considerations. Here are some key points to consider:

1. Academic Reputation: Colleges like Magdalen, Trinity, and Christ Church have strong reputations for Mathematics. These colleges often have experienced tutors in Mathematics who can provide excellent guidance and support.

2. Resources and Facilities: Some colleges offer better libraries, study spaces, and access to resources. Colleges with robust Mathematics departments may also have more opportunities for research and collaboration.

3. Social Environment: Each college has its own culture. If you prefer a lively and vibrant atmosphere, you might consider larger colleges like St. John’s or Pembroke, which host more students and have various societies. If you prefer a quieter, more intimate setting, smaller colleges like Merton or New College may be more suitable.

4. Accommodation: Check if the college offers accommodation throughout your degree, especially for first-year students. This can significantly impact your living arrangements and financial planning.

5. Open Applications: If you’re unsure about college-specific fit, consider making an open application. This allows the university to allocate you to a college based on your strengths and the college’s needs.

6. Financial Considerations: Different colleges have varying accommodation costs and financial support options. Investigating these can help in making a financially sound decision.

Ultimately, there is no “best” college universally; it depends on what you value most in your experience. Visit college websites, attend open days, and talk to current students to gain insights into what each college can offer you.