There are 48 people in a class. The head teacher asked: "Who has finished the Chinese homework?" At this time, 37 people raised their hands. Ask again: "Who has finished the math homework?" At this time, 42 people raised their hands. Finally, I asked: "Who hasn't finished their Chinese and math homework?" No one raised their hands. Please do the math, how many people in this class have finished their language and math homework.
一个班有48人．班主任问："谁做完了语文作业？"这时有37人举手．又问："谁做完了数学作业？"这时有42人举手．最后问："谁语文、数学作业都没做完？"没有人举手．请你算一算，这个班语、数作业都做完的有多少人．
<gadget id="calculator">42 - 48</gadget>
<output>-6</output>

<gadget id="calculator">37 + (-6)</gadget>
<output>31</output>

<result>31</result>