A bus passes through 8 stations from the starting station to the terminal station (within these two stations). It is known that a total of 100 passengers got on the bus at the first 6 stations, and a total of 80 people got off at the previous stations except the terminal station, so how many passengers boarded at the first 6 stations and got off at the terminal station?
一辆公共汽车由起点站到终点站(这两站在内)共途经8个车站．已知前6个车站共上车100人，除终点站外前面各站共下车80人，则从前六站上车而在终点站下车的乘客共有多少人．
<gadget id="calculator">100 - 80</gadget>
<output>20</output>

<result>20</result>