The grain store bought 620 kilograms of white flour in July, and 305 kilograms were used up. How many kilograms of white flour do the grain store still have?
粮店七月份买了620千克白面，用去了305千克，粮店现在还有白面多少千克？
<gadget id="calculator">620 - 305</gadget>
<output>315</output>

<result>315</result>