Calculators?
Nope.
Why do you think we tell you to learn your 25x table or practise mental speed/time/distance problems?
Polling you fast-jet at warp 6 you will have one hand on the stick, one on the throtle and the other for any odd bits and pieces. You won't have 2 spare to operate a calculator, especially with gloves on.
Same in training, Pilot or WSO, use the tools provided an dno calculators.