Do you know that many years ago, maths teachers were against the idea of allowing students to use calculators?
Using the calculator for the problems which are to check the technique and the understandings the formula is ok but its not justified to be used by junior for writing the table.
Instead of using the phone its better to allow them use the PC for study.
!ALIVE
Hmm... PC is actually a good idea. I didn't think that far.