The whole school lined up to do exercises. It is known that there are 80 people in the outer layer, so how many students do exercises in this school?
全校排成一方阵做操．已知外层共有80人，那么这个学校共有多少学生做操？
<gadget id="calculator">80 / 4</gadget>
<output>20</output>

<gadget id="calculator">20 + 1</gadget>
<output>21</output>

<gadget id="calculator">21 * 21</gadget>
<output>441</output>

<result>441</result>