An engineering team repaired a section of road. The first phase repaired 1/2 of the total length, and the second phase repaired 800 meters, leaving 30% of the total length unrepaired. How many meters is this road?
某工程队修一段公路，第一期修了全长的(1/2)，第二期修了800米，还剩下全长的30%没有修．这段公路长多少米？
<gadget id="calculator">1 / 2</gadget>
<output>1/2 = around 0.5</output>

<gadget id="calculator">30 / 100</gadget>
<output>3/10 = around 0.3</output>

<gadget id="calculator">1 - (1/2) - (3/10)</gadget>
<output>1/5 = around 0.2</output>

<gadget id="calculator">800 / (1/5)</gadget>
<output>4_000</output>

<result>4_000</result>