A canal is 530 meters long. It has been repaired for 8 days, and there are 218 meters left to be repaired. How many meters are repaired per day on average? (column comprehensive formula)
一条水渠全长530米，已经修了8天，还剩218米没修，平均每天修多少米？(列综合算式)
<gadget id="calculator">530 - 218</gadget>
<output>312</output>

<gadget id="calculator">312 / 8</gadget>
<output>39</output>

<result>39</result>