A carriage has 102 seats on the upper deck, 79 seats on the lower deck, 9 empty seats on the lower deck, and 2 empty seats on the upper deck. How many passengers are there in this carriage?
一节车厢上层有102个座位，下层有79个座位，下层空了9个座位，上层又空了2个座位，这节车厢共有多少名乘客？
<gadget id="calculator">102 + 79</gadget>
<output>181</output>

<gadget id="calculator">9 + 2</gadget>
<output>11</output>

<gadget id="calculator">181 - 11</gadget>
<output>170</output>

<result>170</result>