6 swallows eat 4200 pests in 7 days, how many pests does each swallow eat per day on average?
6只燕子7天吃害虫4200只，平均每只燕子每天吃多少只害虫？
<gadget id="calculator">4_200 / 7 / 6</gadget>
<output>100</output>

<result>100</result>