There is 1 liter of water in a container, and 4 cups are poured out with the same size cup, and there is 400 milliliters left, how many milliliters of each cup of water is poured out.
一个容器中有1升水，用同样大的杯子倒出4杯，还剩400毫升，倒出的每杯水有多少毫升．
<gadget id="calculator">1 * 1_000</gadget>
<output>1_000</output>

<gadget id="calculator">1_000 - 400</gadget>
<output>600</output>

<gadget id="calculator">600 / 4</gadget>
<output>150</output>

<result>150</result>