To build a road, 840 meters have been built, and the full length (3/4) remains. How long is the road in meters?
修一条公路，已经修完840米，还剩下全长的(3/4)．公路全长多少米？
<gadget id="calculator">3 / 4</gadget>
<output>3/4 = around 0.75</output>

<gadget id="calculator">1 - (3/4)</gadget>
<output>1/4 = around 0.25</output>

<gadget id="calculator">840 / (1/4)</gadget>
<output>3_360</output>

<result>3_360</result>