Inflight maths is part of the syllabus, but usually you do that when approximately ready for x-country, i.e. 1/60 rules for interception (keep in mind, we talk partFCL, so extensive CVFR is part of the training), ETA and ETE calculation, xwind, TOD, glidepath, fuel consumed etc etc ... once you fly the plane, you have capacity for the simple pilots calculations, but not before.
At 10hrs?
No, seriously Pat, what maths are you being asked to do?