This is a bit of a cheat but saves working it out:
Climb: -CTM+
Descent: +CTM-
Where C = Indicated or Calibrated Airspeed
T = True Airspeed
M = Mach No
Eg in a climb
Constant C, T and M increase
Constant T, C decreases, M increases
Constant M, C and T decrease
Other way around for a descent.