A pen is 9 yuan, and a schoolbag is 22 yuan. How much is it to buy a pen and a schoolbag?
一枝钢笔9元，一个书包22元，买一枝钢笔和一个书包大约多少元．
<gadget id="calculator">20 + 10</gadget>
<output>30</output>

<result>30</result>