A bus contains 12 double chairs and 8 single chairs. How many passengers can it take in total?
一部大客车，里面有双人椅12张，单人椅8张．一共可以坐多少位乘客？
<gadget id="calculator">12 * 2</gadget>
<output>24</output>

<gadget id="calculator">24 + 8</gadget>
<output>32</output>

<result>32</result>