Kings has a laid back approach to this sort of thing.
The school sells a calculator to the boys which they recommend - very reasonably priced - from memory £5. So wait and see.
I bought my first DS a French and German dictionary which he never seemed to use. I didn't bother for DS2. Equally DS2 has never had a DT Apron as he says they are at school already.
My advice would be 'wait and see'. They can also be a few weeks sorting out lockers and thumb prints for dinners which at the time I found puzzling although DSs were not bothered