After a railway has been repaired for 800 kilometers, the rest is 300 kilometers less than the total length (3/4). How many kilometers is this railway?
一条铁路修了800千米后，剩下的比全长的(3/4)少300千米，这条铁路长多少千米？
<gadget id="calculator">800 - 300</gadget>
<output>500</output>

<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">500 / (1/4)</gadget>
<output>2_000</output>

<result>2_000</result>