How many 200ml paper cups can be filled with 4 liters of water in an electric kettle?
一个电水壶有4升水，能倒满多少个200毫升的纸杯．
<gadget id="calculator">4 * 1_000</gadget>
<output>4_000</output>

<gadget id="calculator">4_000 / 200</gadget>
<output>20</output>

<result>20</result>