The school's newly built teaching building has 4 floors, each floor has 9 classrooms, and each classroom needs to be equipped with 25 sets of desks and stools. How many sets of desks and stools are needed for this new teaching building?
学校新建的教学楼共有4层，每层有9间教室，每间教室要配25套课桌凳．这个新教学楼一共需要进多少套课桌凳？
<gadget id="calculator">25 * 9 * 4</gadget>
<output>900</output>

<result>900</result>