There are 40 students in a certain class, among which 25 students participate in the mathematics interest group, and 27 students participate in the Chinese interest group. At least how many students participate in both groups.
某班有40名学生，其中参加数学兴趣小组的学生有25名，参加语文兴趣小组的学生有27名，两个小组都参加的学生至少有多少名．
<gadget id="calculator">27 - 40</gadget>
<output>-13</output>

<gadget id="calculator">25 + (-13)</gadget>
<output>12</output>

<result>12</result>