A rope is 40 meters long, 12.53 meters are used for the first time, and 23.47 meters are used for the second time, how many meters are left on the rope?
一根绳子长40米，第一次用去12.53米，第二次用去23.47米，这时绳子还剩下多少米？
<gadget id="calculator">40 - 12.53 - 23.47</gadget>
<output>4</output>

<result>4</result>