Use a measuring cup with a capacity of 500ml to fill up the water and pour it into the fish tank 18 times, but it is still not full. How many liters must the capacity of this fish tank be?
用一个容量500ml的量杯接满水向鱼缸倒18次，还没有灌满，这个鱼缸容量一定大于几升？
<gadget id="calculator">18 / 1_000</gadget>
<output>9/500 = around 0.018</output>

<gadget id="calculator">500 * (9/500)</gadget>
<output>9</output>

<result>9</result>