For count digits, you could just convert it to a String and check the length
Sum digits, convert to string then seperate each character with charAt then convert it to numbers in the return statement.
Average digits you can convert it to a String and then convert them back after taking them apart.
What do you mean pieces? Like Laptop components? If so then motherboard,ram,cpu, and psu for a basic laptop so 4 I guess (5 if you want to include a gpu).
