road construction team wants to build a road. It has built the full length (1/5) in the first month, and the full length (1/6) in the second month. There are still 57 kilometers left to be repaired. How long is this road?
某修路队要修一条公路，第一个月修了全长的(1/5)，第二个月又修了全长的(1/6)，还剩下57千米没有修．这条公路有多长？
<gadget id="calculator">1 / 5</gadget>
<output>1/5 = around 0.2</output>

<gadget id="calculator">1 / 6</gadget>
<output>1/6 = around 0.166667</output>

<gadget id="calculator">1 - (1/5) - (1/6)</gadget>
<output>19/30 = around 0.633333</output>

<gadget id="calculator">57 / (19/30)</gadget>
<output>90</output>

<result>90</result>