A rectangular swimming pool, walking along the swimming pool is 280 meters, if the length of the swimming pool is 100 meters, then how many meters is its width?
一个长方形游泳池，沿着这个游泳池走一圈是280米，如果游泳池的长是100米，那么它的宽是多少米．
<gadget id="calculator">280 / 2</gadget>
<output>140</output>

<gadget id="calculator">140 - 100</gadget>
<output>40</output>

<result>40</result>