If a book costs $15 and you have a coupon for $3 off, how much will you pay?

To determine the final price of the book after applying the coupon, first, take the original price of the book, which is $15. Then, subtract the amount of the coupon, which is $3.

So, the calculation is as follows:

$15 (original price) - $3 (coupon discount) = $12 (final price).

Thus, the total you will pay for the book after using the coupon is $12. This calculation illustrates how discounts reduce the price of items, which is a fundamental concept in basic arithmetic and budgeting.