A total of 680 students from Xiabamiao Primary School participated in interest groups, 75 students participated in science and technology classes, and 4 times as many students participated in art classes as science and technology classes. The rest all participated in sports classes. How many people participated in sports classes?
下八庙小学小学共有680名同学参加兴趣小组，参加科技类的有75人，参加艺术类的人数是科技类的4倍，剩下的全部参加体育类，参加体育类有多少人？
<gadget id="calculator">75 * 4</gadget>
<output>300</output>

<gadget id="calculator">680 - 300 - 75</gadget>
<output>305</output>

<result>305</result>