How do you figure out probability?

What is the probability of simultaneously flipping three coins — a penny, a nickel, and a dime — and having all of them land on heads? Using the classic theory, determine the ratio of number of favorable outcomes to the number of total outcomes. So the possibilities would be:
Heads Heads Heads
Heads Heads Tails
Heads Tails Heads
Heads Tails Tails
Tails Heads Heads
Tails Heads Tails
Tails Tails Heads
Tails Tails Tails

As you can see, there are eight different outcomes, only one of which is favorable (all heads). Therefore, the probability of three coins landing heads is 1/8, or .125.