rectangular swimming pool has a perimeter of 200 meters and its length is 20 meters greater than its width. What is the length in meters?
一个长方形游泳池，周长是200米，长比宽多20米，长是多少米？
<gadget id="calculator">200 / 2</gadget>
<output>100</output>

<gadget id="calculator">20 + 100</gadget>
<output>120</output>

<gadget id="calculator">1 + 1</gadget>
<output>2</output>

<gadget id="calculator">120 / 2</gadget>
<output>60</output>

<result>60</result>