The school holds a gymnastics competition. There are 25 classes in the whole school. Each class has 4 rows, and each row has 9 people. How many people participated in total?
学校进行体操比赛，全校有25个班，每班排4行，每行排9人，共有多少人参加？
<gadget id="calculator">4 * 25 * 9</gadget>
<output>900</output>

<result>900</result>