The school library purchased 180 sets of fairy tale books and story books. Each set of fairy tale books is 16.8 yuan, and each set of story books is 13.2 yuan. How much does it cost to buy these books?
学校图书馆购进童话书和故事书各180套．童话书每套16.8元，故事书每套13.2元．购进这些书一共需要多少元？
<gadget id="calculator">16.8 + 13.2</gadget>
<output>30</output>

<gadget id="calculator">30 * 180</gadget>
<output>5_400</output>

<result>5_400</result>