Xiaohong has 16.7 yuan, Xiaoming has 12.8 yuan, and they are still short of 3.3 yuan to buy a set of books. How much is this set of books?
小红有16.7元，小明有12.8元，他们合买一套书还差3.3元．这套书有多少元？
<gadget id="calculator">16.7 + 12.8 + 3.3</gadget>
<output>32.8</output>

<result>32.8</result>