After the No. 208 bus arrives at station A, 9 passengers get off, and 13 passengers get on again. At this time, there are 25 passengers on the bus. How many passengers are there in the car before arriving at Station A?
208路公交车到达A站后，下去9位乘客，又上来13位乘客，这时车上有25位乘客．到达A站前车上原有多少位乘客？
<gadget id="calculator">25 - 13</gadget>
<output>12</output>

<gadget id="calculator">12 + 9</gadget>
<output>21</output>

<result>21</result>