There are 36 students in a class. In a test, 25 students answered the first question correctly, 23 students answered the second question correctly, and 15 students answered both questions correctly. So, how many people are wrong in both questions?
一个班有36个学生，在一次测验中，答对第一题的25人，答对第二题的23人，两题都答对的15人．那么，两题都不对的有多少人．
<gadget id="calculator">23 - 15</gadget>
<output>8</output>

<gadget id="calculator">25 + 8</gadget>
<output>33</output>

<gadget id="calculator">36 - 33</gadget>
<output>3</output>

<result>3</result>