Computer network cables should be laid in the computer room of the school. There is a 200-meter-long network cable, and 124.5 meters are used up. How much shorter is the rest?
学校电脑房要铺设电脑网线．有一根200米长的网线，用去了124.5米，剩下的比用去的短多少米？
<gadget id="calculator">200 - 124.5</gadget>
<output>75.5</output>

<gadget id="calculator">124.5 - 75.5</gadget>
<output>49</output>

<result>49</result>