112 students in the fifth grade participated in the Chinese and Mathematics exams, and each of them got an excellent grade in at least one of them. It is known that 60 students got a good grade in Chinese, and 73 people got a good grade in mathematics.
五年级112名同学参加语文、数学考试，每人至少有一门获优，已知语文获优者60人，数学获优者73人，只有语文一门获优的人数是多少．
<gadget id="calculator">73 - 112</gadget>
<output>-39</output>

<gadget id="calculator">60 + (-39)</gadget>
<output>21</output>

<gadget id="calculator">60 - 21</gadget>
<output>39</output>

<result>39</result>