There are 50 students in class 31, 25 of them like to eat apples, 23 like to eat strawberries, 13 like to eat both apples and strawberries, how many people don't like these two kinds of fruits.
三1班有学生50人，其中25人喜欢吃苹果，23人喜欢吃草莓，13人既喜欢吃苹果，也喜欢吃草莓，这两种水果都不喜欢的有多少人．
<gadget id="calculator">23 - 13</gadget>
<output>10</output>

<gadget id="calculator">25 + 10</gadget>
<output>35</output>

<gadget id="calculator">50 - 35</gadget>
<output>15</output>

<result>15</result>