IAM,
For RAAF aptitude testing (aircrew i am talking here, think ATC have some different ones), there are numerous maths related papers that you get on the day. As far as i am aware, some are marked one way, the others the other way.
As such my advice is: answer as many as quickly as you can, but don't just circle any randomly at the end if you run out. I did that years ago and it worked for me.
Good luck, let us know how you go.