Are you confident with:
Basic addition, multiplication etc
Trigonometry (sine, cosine etc)
Base 60 (degrees, minutes and seconds) calculations
Graph reading
Interpolation/ extrapolation - finding figures from tables or graphs that lie between or beyond the given results
Exponents - x squared or cubed, 10 to the power x etc etc
Basic physics - F=ma, moments, resolution of forces type of thing
If so, don't need to know much more. If not, the 'outlay' might be needed. What about finding a local maths teacher that does private GCSE/ A-level lessons? You don't need anymore than basic stuff and that might be cheaper/ easier.