A bus goes to Renmin Road, 12 people get off, and 7 people get on the bus. At this time, there are 30 passengers on the bus. There were x passengers in the car. x= how much
一辆公共汽车，到人民路有12人下车，有7人上车，这时车上有乘客30人．车上原有乘客x人．x=多少
<gadget id="calculator">30 - 7</gadget>
<output>23</output>

<gadget id="calculator">23 + 12</gadget>
<output>35</output>

<result>35</result>