Two information is necessary to solve a formula
Variables are usually common for all waypoints, they are stored in cache note.
There could be more waypoints with different formulas, we store formulas in waypoint note.
The cache note has two modes. If there is a pencil in the top right corner, you are editing general note. if there is (X)= in the corner, you are editing variables.
(1) Adjust formula so that the first line of the formula is for the latitude (N/S) and the other for the longitude (E/W)
(2) Open formula solver tapping Calculate formulas
Edit formulas to follow basic syntax rules:
Use the Normalize formulas to simplify editing:
Now, we can try Calculate formulas