Just a thought, but generally apptitude tests measure the most basic elements of any given skill set, ie math, reading comprehension, sciences, etc.
If a trade requires that you are strong in math, and you aren‘t, then pursuing that trade may ultimately be setting yourself up for a very difficult time. Things are going to move very quickly when you get to your MOC training, and (this is just my opinion)I personaly wouldn‘t want to find myself dealing with the frusteration of always feeling a step behind coupled with the fact that I was still trying to adjust to military life.
Showing up to your first day of SigOp training weak in the area of math, is no different than showing up to your first day of Infantry training weak in the area of fitness. It‘s going to be hard enough on the prepared.
I would suggest that if you really want to pursue that trade, or any other math heavy trade, that you spend some time upgrading your math at school or nightschool. Obviously there isn‘t any time to do that before you take your apptitude test, but if you should be qualified for SigOp after you do take it, then that would be my suggestion for the time that you are waiting for the rest of your application to move forward.
As I said, just a thought.
Good luck on your apptitude test!