John has $40 to spend at the yard sale. He buys 6 books for $2 each. He would like to spend the rest of his money on model cars for his collection. If he cars cost $7 each, how many can he buy? Explain.

4 cars; possible explanation: rst I found how much John spent on books; 6 * 2 = $12. I then subtracted $12 from $40 to nd how much money he has left; $40 - $12 = $28. Finally, I divided $28 by 7 to see how many cars he could buy; $28 : 7 = 4