A rope is 20 meters long, and 13.6 meters are used for the first time. The second time I used 2.8 meters. How much shorter is the rope than the original?
一根绳子长20米，第一次用去13.6米．第二次用去了2.8米．这根绳子比原来短了多少米？
<gadget id="calculator">13.6 + 2.8</gadget>
<output>16.4</output>

<result>16.4</result>