Mike, no problem - it was 4 years ago though and for a different airline so it may or may not be accurate now, as Shorty says.
Shorty - most places provide everything you'll need but if you do take a calculator you can't go wrong..? Don't remember the controls being reversed?! I was similar age when I did the tests (ie half a lifetime away from GCSEs!) and don't remember there being anything beyond GCSE in the maths. Seem to remember the main challenge there is acheiving accuracy in the time. Of course, this was 4 years ago...
Anyway, enjoy