Mom bought some plums, my elder brother ate 5, and my younger brother ate 4, exactly half of them. How many plums did Mom buy?
妈妈买回一些李子，哥哥吃了5个，弟弟吃了4个，正好吃了一半．妈妈买回的李子一共有多少个？
<gadget id="calculator">5 + 4</gadget>
<output>9</output>

<gadget id="calculator">9 * 2</gadget>
<output>18</output>

<result>18</result>