There are 36 people in class 31, 23 people like apples, 18 people like bananas, everyone likes to eat at least one kind, so how many people like to eat both.
三1班有36人，喜欢吃苹果的有23人，喜欢吃香蕉的有18人，每人至少喜欢吃一种，那么两种都喜欢吃的有多少个人．
<gadget id="calculator">23 + 18</gadget>
<output>41</output>

<gadget id="calculator">41 - 36</gadget>
<output>5</output>

<result>5</result>