Pour 2 liters of water from container A into container B. At this time, container A and container B have the same amount of water. It turns out that container A holds more water than container B by how many liters.
将甲容器里的2升水倒入乙容器，这时甲容器和乙容器里的水就一样多，原来甲容器比乙容器多盛水多少升．
<gadget id="calculator">2 * 2</gadget>
<output>4</output>

<result>4</result>