Xiao Ming has already typed a 3000-word manuscript for 30 minutes. He has typed a total of 1800 words. How much time is left to finish?
小明要完成3000字的稿件打印，已经打了30分钟，一共打了1800个字，剩下需要多少时间完成？
<gadget id="calculator">3_000 - 1_800</gadget>
<output>1_200</output>

<gadget id="calculator">1_800 / 30</gadget>
<output>60</output>

<gadget id="calculator">1_200 / 60</gadget>
<output>20</output>

<result>20</result>