To dig a canal, 20% was dug on the first day, 60% was dug on the second day, and there were 320 meters left to be dug. How many meters is this canal?
挖一条水渠，第一天挖了20%，第二天挖了60%，还剩320米没有挖．这条水渠长多少米？
<gadget id="calculator">20 / 100</gadget>
<output>1/5 = around 0.2</output>

<gadget id="calculator">60 / 100</gadget>
<output>3/5 = around 0.6</output>

<gadget id="calculator">1 - (1/5) - (3/5)</gadget>
<output>1/5 = around 0.2</output>

<gadget id="calculator">320 / (1/5)</gadget>
<output>1_600</output>

<result>1_600</result>