The store shipped 7 boxes of eggs and 7 boxes of duck eggs. Each carton of eggs weighs 26 kilograms, and each carton of duck eggs weighs 31 kilograms. How many kilograms of eggs and duck eggs are shipped from the store?
商店运来鸡蛋和鸭蛋各7箱．鸡蛋每箱重26千克，鸭蛋每箱重31千克，商店一共运来的鸡蛋和鸭蛋共多少千克？
<gadget id="calculator">26 + 31</gadget>
<output>57</output>

<gadget id="calculator">57 * 7</gadget>
<output>399</output>

<result>399</result>