Hey,
It was 5 years ago when I did the selection process at CTC so things may well have changed since I did it. However, I have also done the RAF Aircrew and Naval Aircrew tests at Cranwell, they were much harder, so if I tell you about them I guess it will prepare you more for what to expect.
1. Speed, distance, time calculations; Obvious what to expect, you'll be given information and have to an answer to one of the three parameters. Practice this but also using different units, ie xKm/H for yMin = ZMiles. If I remember correctly if the mixed units do come up they give you a conversion.
2. Fuel burn; These were as simple as ''If you burn 12KG of fuel/hour and are flying for 3hours 15min how much fuel would you use'', or as complex as ''you have 1000kg of fuel, you burn 250KG/h for 3 hours, after an engine failure your fuel burn decreases to 195KG/h, you fly for an extra 45min, on landing how much fuel is left''
3. Meeting points; You are given the distance between two airfields, from where two aircraft depart, at different times and different speeds. From that information you have to work out either the time they cross, the distance from a certain airfield they cross, or both.
4. Addition, Subtraction, Multiplication and Division; Self explanatory. The numbers were simple, if there was a decimal then it was an easy one, not like 5.6752
5. Sequences; 2 4 6 8 10.. whats the 9th number in the sequence
I think that pretty much covers it if I'm honest. The best advice I can give you about the tests is, enjoy it. But compared to the forces tests you're in for a breeze, they'll last maybe an hour, opposed to the 6-7 that you'd have at Cranwell.