Experience the power of a bookbook
https://www.youtube.com/watch?v=MOXQo7nURs0
Watched over 9.7 million times.
Battery life, fragility of the medium, other distractions with an internet capable device...kids should master the material as someone further downthread points out, else they think learning is just sweeping their eyes across an electronic screen.
Had the battery die in an old brick sized Texas Instruments calculator during my high school physics final back when dinosaurs walked the earth...
Oh noes!
But...I had a math text book with log tables in the back in my book bag, voila, extra credit!
Later in life:
Artillery fire direction computations using charge sticks and firing tables were faster and just as accurate as with the handheld computers they transitioned to in the ‘80s.
We did still needed the radios and field phones though!
No ‘call out your numbers loud and clear’, the guns were a little too far away for that