A person walks a distance, has traveled the full length (1/3), and has 400 meters left. How many meters is this road?
某人行一段路，已经行了全长的(1/3)，还剩下400米．这段路长多少米？
<gadget id="calculator">1 / 3</gadget>
<output>1/3 = around 0.333333</output>

<gadget id="calculator">1 - (1/3)</gadget>
<output>2/3 = around 0.666667</output>

<gadget id="calculator">400 / (2/3)</gadget>
<output>600</output>

<result>600</result>