Consider the question. John plants a plot of 3 trees by 4 trees. Each tree gives 5 apples. He sells each apple for $.5. How much money does he make, in dollars?
 If the answer is '30'; explain the reasoning:
He has 3 * 4 = 12 trees. So he has 12 * 5 = 60 apples. So he sells the apples for 60 * .5 = $30.