A store shipped 6400kg of rice, 2200kg has been sold, and the rest is planned to be sold out within 7 days. How many kilograms are sold per day on average?
一个商店运来6400千克大米，已经售出2200千克，余下的计划7天售完．平均每天要售出多少千克？
<gadget id="calculator">6_400 - 2_200</gadget>
<output>4_200</output>

<gadget id="calculator">4_200 / 7</gadget>
<output>600</output>

<result>600</result>