A canal can be dug 60 meters per day, which can be completed in 24 days. Now the project needs to be completed 4 days ahead of schedule, how many meters should be dug every day? (Solve with ratio)
一条水渠每天挖60米，24天可以完成．现在要提前4天完工，每天要挖多少米？(用比例解)
<gadget id="calculator">60 * 24</gadget>
<output>1_440</output>

<gadget id="calculator">24 - 4</gadget>
<output>20</output>

<gadget id="calculator">1_440 / 20</gadget>
<output>72</output>

<result>72</result>