Container A holds 800 ml of water, and container B holds 1200 ml of water. How many milliliters of water is poured from container B into container A, and the water in both container A and container B is the same.
甲容器里盛水800毫升，乙容器里盛水1200毫升，从乙容器中倒多少毫升的水给甲容器，甲、乙容器里的水同样多．
<gadget id="calculator">1_200 - 800</gadget>
<output>400</output>

<gadget id="calculator">400 / 2</gadget>
<output>200</output>

<result>200</result>