The perimeter of a rectangular lawn is 240 meters, the length is 70 meters, and the width is how many meters.
一个长方形的草坪周长是240米，长是70米，宽是多少米．
<gadget id="calculator">240 / 2</gadget>
<output>120</output>

<gadget id="calculator">120 - 70</gadget>
<output>50</output>

<result>50</result>