Caizhan originally stored several kilograms of Chinese cabbage in winter. Half of the original Chinese cabbage was sold on the first day. 200 kg were shipped the next day. On the third day, half of the existing cabbage and 30 kg were sold, and the result was 1800 kg of three times the remaining cabbage. How many kilograms of Chinese cabbage should be stored in the original winter?
菜站原有冬贮大白菜若干千克．第一天卖出原有大白菜的一半．第二天运进200千克．第三天卖出现有白菜的一半又30千克，结果剩余白菜的3倍是1800千克．求原有冬贮大白菜多少千克？
<gadget id="calculator">1_800 / 3</gadget>
<output>600</output>

<gadget id="calculator">600 + 30</gadget>
<output>630</output>

<gadget id="calculator">630 * 2</gadget>
<output>1_260</output>

<gadget id="calculator">1_260 - 200</gadget>
<output>1_060</output>

<gadget id="calculator">1_060 * 2</gadget>
<output>2_120</output>

<result>2_120</result>