40 students in the sixth grade participate in interest group activities, among them (1/5) participate in the science and technology group, (3/10) students participate in the computer group, and the rest of the students participate in the track and field group. How many people participate in the track and field group?
六年级40人参加兴趣小组活动，其中有(1/5)参加科技组，有(3/10)的学生参加电脑组，其余的学生参加田径组，参加田径组的有多少人？
<gadget id="calculator">1 / 5</gadget>
<output>1/5 = around 0.2</output>

<gadget id="calculator">40 * (1/5)</gadget>
<output>8</output>

<gadget id="calculator">3 / 10</gadget>
<output>3/10 = around 0.3</output>

<gadget id="calculator">40 * (3/10)</gadget>
<output>12</output>

<gadget id="calculator">8 + 12</gadget>
<output>20</output>

<result>20</result>