Tiantian prayed for the children in the earthquake-stricken area, and planned to fold 1,000 paper cranes. She folded 40 cranes every day. After a week of folding, she planned to fold 20 more than before.
甜甜为地震灾区的小朋友祈福，准备折1000只纸鹤，她每天折40只，折了一周后剩下的她计划每天比原来多折20只，她再折几天才能折完？
<gadget id="calculator">40 * 7</gadget>
<output>280</output>

<gadget id="calculator">1_000 - 280</gadget>
<output>720</output>

<gadget id="calculator">20 + 40</gadget>
<output>60</output>

<gadget id="calculator">720 / 60</gadget>
<output>12</output>

<result>12</result>