There are 27 people on a bus, 9 people get off at the station in front, and then 18 people get on, how many people are there on the bus now?
一辆公交车坐了27人、到前方车站下去9人，后来又上来18人，车上现在又有多少人？
<gadget id="calculator">27 - 9</gadget>
<output>18</output>

<gadget id="calculator">18 + 18</gadget>
<output>36</output>

<result>36</result>