To lay a water pipe, the full length (5/9) has been laid, and there is still 800 meters left. How long is this water pipe in meters?
铺一条水管，已经铺了全长的(5/9)，还剩下800米，这条水管长多少米？
<gadget id="calculator">5 / 9</gadget>
<output>5/9 = around 0.555556</output>

<gadget id="calculator">1 - (5/9)</gadget>
<output>4/9 = around 0.444444</output>

<gadget id="calculator">800 / (4/9)</gadget>
<output>1_800</output>

<result>1_800</result>