Check out your local library, there may be a career or skills improvement section, and within it will be books on numerical reasoning for interviews etcetera. These types of questions tend to be the same across the board, so it's worth checking out these books.
If you don't have access to a library, or prefer to use a piece of software, the numerical reasoning content supplied in the software by PilotAptitudeTest.com seems to get positive reviews from guys using it for CTC Aviation assessment, and the FTE Jerez assessment is exactly the same.