The store bought 800 kg of apples, and after selling them for 3 days, there were 170 kg left. How many kilograms of apples are sold on average per day?
商店买来苹果800千克，卖了3天后还剩170千克．平均每天卖苹果多少千克？
<gadget id="calculator">800 - 170</gadget>
<output>630</output>

<gadget id="calculator">630 / 3</gadget>
<output>210</output>

<result>210</result>