5 x 30 min interviews
2-3 maths problems per interview
Practised explaining thoughts on the spot to a family membrane
Practice papers
Don't cram before the interview
Remember this advice isn't official. There is no guarantee it will reflect your experience because university applications can change between years. Check the official Cambridge and Oxford websites for more accurate information on this year's application format and the required tests.
Also, someone else's experience may not reflect your own. Most interviews are more like conversations than tests and like, any conversation, they are quite interactive.
Test taken: Mathematics Admissions Test (MAT)
Number of interviews: 5
Time between interviews: A day, or several hours.
Length of interviews: About 30 minutes.
Online interview: No
I was given several maths problems to look at - usually 2 or 3 per interview. The interviewers were friendly and tried to guide me along as I went through the problems. The problems were varied including logic, calculus and graph sketching. I wasn't really asked anything about my personal statement or reading etc.
I did some revision of A level content, I found some practice maths interview questions online. I also used some maths olympiad questions. Most importantly I practised doing questions with a family member - explaining my thoughts on the spot as I answered the question.
Lots and lots of practice papers, available on the Oxford Maths website, also some Step 1/2 papers.
Try to stay calm in the interview, the interviewers want you to do your best, not catch you out. They want to see your potential and understanding, if you forget a formula you can ask them and I don't think it would reflect badly on you. Definitely practice doing problems out loud and on the spot as that was something I wasn't used to. I personally would say to not do loads of cramming right before the interview, just try to relax for a bit.