Many universities include ability tests, in their selection process. These will test your maths ability and literacy. These may be held on the same day as your interview, or perhaps a different day, and your invite to interview will depend on these results. Sometimes, if candidates have scored well on their university application they choose not to hold ability tests. Other universities always use these.
These questions are designed to test specific aptitudes such as numerical skills (basic maths) and verbal reasoning (your ability to think through and evaluate written statements).
These types of test are usually multiple choice so have a go even if you aren’t sure of the answer. You will often have a set amount of time to complete them, and may run out of time before you have finished. Try to finish if you can but don’t worry too much of you don’t, it’s not as important as you might think. Just get through what you can.