Calculators (and related mental activities) as hobby or as avocation?

[Jlouis]

Yes, hobby, why not?

Unless you are a professional., which is not my case.

And my doctor prescribed hobbies for mental health, that's why I play a lot with calculators and a game...that have kings, Queens, Knights....I forgot the name. Very good for the brain. My doctor said they could prevent a disease...called....alz...something...I really can't remember the name.