In a primary school, the number of people participating in outdoor activities is 480 more than the number of indoor activities. If the number of people participating in outdoor activities increases by 120, then the number of people participating in outdoor activities is exactly 5 times that of indoor sports. How many people originally participated in the indoor activities?
某小学原来参加室外活动的人数比参加室内活动的人数多480人，如果参加室外活动的人数又增加120人，那么参加室外活动的人数正好是参加室内运动的5倍．问原来参加室内活动的有多少人？
<gadget id="calculator">120 + 120 + 480</gadget>
<output>720</output>

<gadget id="calculator">5 - 1</gadget>
<output>4</output>

<gadget id="calculator">720 / 4</gadget>
<output>180</output>

<gadget id="calculator">180 + 120</gadget>
<output>300</output>

<result>300</result>