To build a road, what has been repaired is not repaired (3/5), and 840 meters have been repaired. How long is this road in meters?
修一条公路，已修的是未修的(3/5)，已修840米，这条公路长多少米．
<gadget id="calculator">3 / 5</gadget>
<output>3/5 = around 0.6</output>

<gadget id="calculator">840 / (3/5)</gadget>
<output>1_400</output>

<gadget id="calculator">1_400 + 840</gadget>
<output>2_240</output>

<result>2_240</result>