12 h x $5/h. find the product list the units explain all of your work. answer and explain every step be clear about it.

This is a very simple but very useful example of dimensional analysis. 
12 hours * 5 dollars / hour means that you can cancel the hours out.
One (hours) is in the numerator.
One (hour) is in the denominator.

The plural singular difference does not matter in mathematics.
12 * 5 dollars = 60 dollars.

60 dollars  <<<<< answer

The correct answer is $90