The classic calculator does not have a program (especially an operating system) and performs the simplest arithmetic operations without the help of a processor, but only using a manually controlled arithmetic logic unit (ALU).
An important difference between any calculator and a personal computer is that it can only process numbers. But there are many computers with the same limitations.
Remember: The process of learning a person lasts a lifetime. The value of the same knowledge for different people may be different, it is determined by their individual characteristics and needs. Therefore, knowledge is always needed at any age and position.