The length of the rectangular playground is 80 meters, and the width is long (1/2). What is the area of the playground in square meters?
长方形操场的长是80米，宽是长的(1/2)．操场的面积是多少平方米．
<gadget id="calculator">80 / 2</gadget>
<output>40</output>

<gadget id="calculator">40 * 80</gadget>
<output>3_200</output>

<result>3_200</result>