Two dragonflies can eat 6,720 mosquitoes in 8 days. How many mosquitoes do they eat on average every day?
2只蜻蜓8天能吃蚊子6720只，平均每天吃蚊子多少只？
<gadget id="calculator">6_720 / 8 / 2</gadget>
<output>420</output>

<result>420</result>