pencil is 180mm long and 7cm is used up, how many centimeters are left?
一支铅笔长180毫米，用掉7厘米，还剩下多少厘米？
<gadget id="calculator">180 / 10</gadget>
<output>18</output>

<gadget id="calculator">18 - 7</gadget>
<output>11</output>

<result>11</result>