The third-grade students of the experimental primary school perform gymnastics. There are 21 people in each row, and there are 21 rows. How many students are there in the third grade?
实验小学三年级学生进行体操表演，每排21人，排了21排，三年级共有多少名学生？
<gadget id="calculator">21 * 21</gadget>
<output>441</output>

<result>441</result>