why calculater always counts?

It's like asking yourself, why do you need shoes! Like the computers we use today (the calculator is actually a mini-computer itself), the calculator was invented to make life for mathematians, engineers, accountants, etc. life easier. Ever tried getting the Log or Sin using tables? I don't even want to imagine doing so! =)

Its needed for our everyday life. My phone has a calculator, it comes in handy everytime i go to the grocery store.

calculator counts since it is calculator

I think that the only reason a calculator counts stuff for us is that. because it is made to do that. Its exsistence serves only that purpose and it has been programmed to do so. It wouldn't anything apart from what it has been made to do.