40 students from class 5 and 4 participated in the field and track competitions in the school sports meeting. There are 26 people participating in the field competition and 30 people participating in the track competition. How many people participate in both?
五4班40名同学都参加了校运会中的田赛和径赛．参加田赛的有26人，参加径赛的有30人，两项都参加的有多少人？
<gadget id="calculator">30 - 40</gadget>
<output>-10</output>

<gadget id="calculator">26 + (-10)</gadget>
<output>16</output>

<result>16</result>