A batch of rice was shipped from the school cafeteria, half of it was used for the first time, 200 kg was used for the second time, and the remaining half was used for the third time, leaving 170 kg. How much is the rice in this batch?
学校食堂运来一批大米，第一次用掉全部的一半，第二次又用去200千克，第三次用去剩下的一半，还剩170千克，这批大米多少千克？
<gadget id="calculator">170 * 2</gadget>
<output>340</output>

<gadget id="calculator">340 + 200</gadget>
<output>540</output>

<gadget id="calculator">540 * 2</gadget>
<output>1_080</output>

<result>1_080</result>