To build a road, repair 380m in the first month and 420m in the second month, leaving (3/5) unrepaired. How long is this road in meters?
修一条公路，第一个月修380m，第二个月修420m，还剩下(3/5)没修．这条公路全长多少米？
<gadget id="calculator">380 + 420</gadget>
<output>800</output>

<gadget id="calculator">3 / 5</gadget>
<output>3/5 = around 0.6</output>

<gadget id="calculator">1 - (3/5)</gadget>
<output>2/5 = around 0.4</output>

<gadget id="calculator">800 / (2/5)</gadget>
<output>2_000</output>

<result>2_000</result>