certain place needs to dig a 600-meter-long tunnel. In the first week, it took 5 days to dig an average of 64 meters per day. In the second week, it plans to dig 70 meters per day. How many days will it take to complete?
某地要挖一条长600米长的隧道，第一周挖了5天，平均每天挖64米，第二周准备每天挖70米，还要挖多少天才能完成？
<gadget id="calculator">64 * 5</gadget>
<output>320</output>

<gadget id="calculator">600 - 320</gadget>
<output>280</output>

<gadget id="calculator">280 / 70</gadget>
<output>4</output>

<result>4</result>