There are 35 passengers in a car, 15 people get off at the satellite square, and 11 people get on the car. How many passengers were on the bus when leaving the square?
一辆汽车上有乘客35人，到卫星广场下车15人，上车11人．离开广场时车上有乘客多少人？
<gadget id="calculator">35 - 15</gadget>
<output>20</output>

<gadget id="calculator">20 + 11</gadget>
<output>31</output>

<result>31</result>