A bucket of water, pour out half of it for the first time, then pour 30 kg back into the bucket, pour out half of the remaining water in the bucket for the second time, pour out 180 kg for the third time, and there is still 80 kg in the bucket. How many kilograms of water was in the bucket?
一桶水，第一次倒出一半，然后倒回桶里30千克，第二次倒出桶中剩下水的一半，第三次倒出180千克，桶中还剩下80千克．桶里原来有水多少千克．
<gadget id="calculator">180 + 80</gadget>
<output>260</output>

<gadget id="calculator">260 * 2</gadget>
<output>520</output>

<gadget id="calculator">520 - 30</gadget>
<output>490</output>

<gadget id="calculator">490 * 2</gadget>
<output>980</output>

<result>980</result>