The school bought 5 bookshelves, each with 4 layers, and each layer can hold 100 books. How many books can these bookshelves hold?
学校买来5个书架，每个书架有4层，每层可放100本书，这些书架可放多少本书？
<gadget id="calculator">100 * 4 * 5</gadget>
<output>2_000</output>

<result>2_000</result>