The school builds a new four-story teaching building, each floor has 6 classrooms, and each classroom needs to be equipped with 25 sets of double desks and chairs. How many sets of desks and chairs does the school need to buy?
学校新建一幢四层的教学楼，每层有6间教室，每间教室要配25套双人课桌椅，学校需要购进多少套课桌椅？
<gadget id="calculator">6 * 4</gadget>
<output>24</output>

<gadget id="calculator">25 * 24</gadget>
<output>600</output>

<result>600</result>