A railway, after repairing 900 kilometers, the remaining part is 300 kilometers less than the total length (3/4), how many kilometers is this railway?
一条铁路，修完900千米后，剩余部分比全长的(3/4)少300千米，这条铁路长多少千米？
<gadget id="calculator">900 - 300</gadget>
<output>600</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">600 / (1/4)</gadget>
<output>2_400</output>

<result>2_400</result>