As for when it was first used we do not exactly know. But we are sure that through time people have developed new ways.

  http://www.qubit.org/intros/comp/inset2.html

 http://www.qubit.org/intros/comp/comp.html#furtherreading

 Both these sites offer good information on the basics of quantum computing. While reading you will discover some more advanced problems and arithmetic.

Quantum Computing home page | What is quantum? | When was it first used?