For the maths 'test' which is done in the first week I think do not be worried whatsoever! It's a small diagnostic maths test from a P6 maths practice book, it tests things like adding, subtracting, dividing, decimals, percentages.
The mark does not count towards anything, its basically a means of assessing the needs of the group, and will identify those that, perhaps need some remedial help with maths skills. These people will be invited to go as a group to a a few maths sessions run by the learning development centre at QUB, and they help you through everything step by step to bring you up to scratch.
It's basically in preparation for the nursing calculation exams which are done at the end of every year; these are medicine calculations ie. how many pills/ how much fluid to draw up for injections, but you don't need to worry about those.
And for the uniforms yea you pay when you get measured up for your uniform, do bring cash as you won't be able to pay by card.