There are 2 bookshelves in the teacher's book corner, each with 3 floors, and each floor can hold 20 books. How many books can be put in total?
教室师图书角有2个书架，每个书架有3层，每层能放20本书．一共能放多少本书？
<gadget id="calculator">20 * 3 * 2</gadget>
<output>120</output>

<result>120</result>