Students from 4 classes in the third grade participated in the rope skipping competition. Each class had 2 groups of 15 students. How many students participated in the competition?
三年级4个班的同学参加跳绳比赛，每班2组，每组15人，一共有多少同学参加比赛？
<gadget id="calculator">4 * 2 * 15</gadget>
<output>120</output>

<result>120</result>