To build a road, the full length (1/2) will be 2 kilometers longer on the first day, and the remaining (1/2) will be 1 kilometer shorter on the second day, leaving 20 kilometers unfinished. This road How many kilometers is the total length?
修一条公路，第一天修全长的(1/2)多2千米，第二天修余下的(1/2)少1千米，还剩下20千米没有修完，这条公路全长多少千米？
<gadget id="calculator">20 - 1</gadget>
<output>19</output>

<gadget id="calculator">1 / 2</gadget>
<output>1/2 = around 0.5</output>

<gadget id="calculator">1 - (1/2)</gadget>
<output>1/2 = around 0.5</output>

<gadget id="calculator">19 / (1/2)</gadget>
<output>38</output>

<gadget id="calculator">38 + 2</gadget>
<output>40</output>

<gadget id="calculator">40 / (1/2)</gadget>
<output>80</output>

<result>80</result>