There are 36 people in a travel agency, 24 of them can speak English, 18 can speak Japanese, 4 can neither, how many can know both?
一个旅行社共有36人，其中会英语的有24人，会日语的有18人，两样都不会的有4人，两样都会的有几个？
<gadget id="calculator">36 - 4</gadget>
<output>32</output>

<gadget id="calculator">18 - 32</gadget>
<output>-14</output>

<gadget id="calculator">24 + (-14)</gadget>
<output>10</output>

<result>10</result>