A child bought a 20 cm long pencil, used it up 6.5 cm last week, and used up another 5.5 cm this week. How long is the pencil now?
一位小朋友买了一支20厘米长的铅笔，上周用去了6.5厘米，本周又用去了5.5厘米，这支铅笔现在长多少厘米？
<gadget id="calculator">6.5 + 5.5</gadget>
<output>12</output>

<gadget id="calculator">20 - 12</gadget>
<output>8</output>

<result>8</result>