It is supposed to have so many at once? Avast has a lot of task at once, how many is it supposed to have at once?
It rather depends on which you are talking about.
For instance have a look have a look at your browser processes are running in task manager, the more tabs you have open the more processes will be running, etc.
It is similar for Avast, but to actually speed things up rather than one process performing multiple tasks you have multiple processes performing many tasks quicker.
Also it depends on which Avast Program you are running and which components you have installed, neither of which you have mentioned, so it is hard to comment/compare.