A canal has been built (7/8), and there are 18 kilometers left. How long is this canal?
修一条水渠，已经修了(7/8)，剩下18千米，这条水渠有多长？
<gadget id="calculator">7 / 8</gadget>
<output>7/8 = around 0.875</output>

<gadget id="calculator">1 - (7/8)</gadget>
<output>1/8 = around 0.125</output>

<gadget id="calculator">18 / (1/8)</gadget>
<output>144</output>

<result>144</result>