section of cable is erected from A to B, the ratio of the installed length to the un-installed length is 1:3, and after another 300 meters, the ratio of the installed and un-installed length is 1:2, the length of the cable between A and B How much rice?
从甲地到乙地架设一段电缆，已架设的长度与未架设的长度比是1：3，再架设300米后，已架设和未架设的长度比是1：2，甲乙两地的电缆长多少米？
<gadget id="calculator">1 + 2</gadget>
<output>3</output>

<gadget id="calculator">1 / 3</gadget>
<output>1/3 = around 0.333333</output>

<gadget id="calculator">1 + 3</gadget>
<output>4</output>

<gadget id="calculator">1 / 4</gadget>
<output>1/4 = around 0.25</output>

<gadget id="calculator">(1/3) - (1/4)</gadget>
<output>1/12 = around 0.083333</output>

<gadget id="calculator">300 / (1/12)</gadget>
<output>3_600</output>

<result>3_600</result>