A road has already been repaired (2/5), and if another 200 meters are repaired, half of the road can be repaired. How many meters is this road?
一条公路已经修了它的(2/5)，再修200米，就能修好这条路的一半．这条公路长多少米？
<gadget id="calculator">1 / 2</gadget>
<output>1/2 = around 0.5</output>

<gadget id="calculator">2 / 5</gadget>
<output>2/5 = around 0.4</output>

<gadget id="calculator">(1/2) - (2/5)</gadget>
<output>1/10 = around 0.1</output>

<gadget id="calculator">200 / (1/10)</gadget>
<output>2_000</output>

<result>2_000</result>