The engineering team is going to repair a section of the subway, and 40% of it has been repaired. There are still 900 meters left to be repaired. How long is this section of the subway?
工程队要修一段地铁，已经修了40%，还剩900米没有修，这段地铁长多少米？
<gadget id="calculator">40 / 100</gadget>
<output>2/5 = around 0.4</output>

<gadget id="calculator">1 - (2/5)</gadget>
<output>3/5 = around 0.6</output>

<gadget id="calculator">900 / (3/5)</gadget>
<output>1_500</output>

<result>1_500</result>