Bottle A holds 200ml of water and bottle B holds 800ml of water. How many milliliters of water are poured from bottle B to bottle A, and the two bottles hold the same amount?
甲瓶盛水200毫升，乙瓶盛水800毫升．从乙瓶倒多少毫升水给甲瓶，两瓶盛一样多？
<gadget id="calculator">800 - 200</gadget>
<output>600</output>

<gadget id="calculator">600 / 2</gadget>
<output>300</output>

<result>300</result>