There are a total of 120 students in the sixth grade of a certain school, each of whom participates in at least one of the computer interest group and the science and technology interest group, among which (3/4) students participate in the computer interest group, (7/12) students participate in the science and technology interest group. How many students participated in both interest groups?
某校六年级一共有120名学生，每人至少参加电脑兴趣小组和科技兴趣小组中的一个，其中(3/4)的同学参加电脑兴趣小组，(7/12)的同学参加科技兴趣小组．两种兴趣小组都参加的学生一共有多少名？
<gadget id="calculator">3 / 4</gadget>
<output>3/4 = around 0.75</output>

<gadget id="calculator">7 / 12</gadget>
<output>7/12 = around 0.583333</output>

<gadget id="calculator">(7/12) - 1</gadget>
<output>-5/12 = around -0.416667</output>

<gadget id="calculator">(3/4) + (-5/12)</gadget>
<output>1/3 = around 0.333333</output>

<gadget id="calculator">120 * (1/3)</gadget>
<output>40</output>

<result>40</result>