A steel bar has a total length of 33.8 meters. The first time I used 9.9 meters to make a cage, and the second time I used 15.2 meters to make a guardrail. How many meters are left?
一根钢条全长33.8米，第一次用去了9.9米做笼子，第二次用去了15.2米做护栏，还剩多少米？
<gadget id="calculator">33.8 - 9.9 - 15.2</gadget>
<output>8.7</output>

<result>8.7</result>