Lewis earned $210 mowing lawns during the summer months. He bought 6 comic books worth $13 each using his lawn-mowing money. How much money was left after he bought the comic books?

First you do 6 times 13 getting 78. Then you subtract 210 by 78 getting a final answer of $132

You can find the total amount Lewis spent on comic books by multiplying 6 by 13, as he purchased 6 comic books which each cost $13.

6 * $13 = $78

Then, you can subtract that amount from Lewis' earnings from mowing lawns to find how much money he had left after buying the comic books.

$210 - $78 = $132