The students form a square to play games, 20 people stand on each side, there are people at the four vertices, how many people are there in the outermost circle?
同学们围成一个正方形做游戏，每边站20人，四个顶点都有人，最外圈一共有多少人．
<gadget id="calculator">20 * 4</gadget>
<output>80</output>

<gadget id="calculator">80 - 4</gadget>
<output>76</output>

<result>76</result>