To build a road, the ratio of the length of the already repaired to the unrepaired length is 1:3, and then repair 300 meters, the length of the already repaired is not repaired (1/2), how many kilometers have been repaired in total?
修一条公路，已经修的和没有修的长度比是1：3，再修300米，已经修的长度是没有修的(1/2)，共修了多少千米？
<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>

<gadget id="calculator">(1/3) / 1_000</gadget>
<output>1/3_000 = around 0.000333</output>

<gadget id="calculator">3_600 * (1/3_000)</gadget>
<output>6/5 = around 1.2</output>

<result>6/5 = around 1.2</result>