Dig a canal, already dug (2/3), and there are 30 meters left, what is the total length of this canal in meters?
挖一条水渠，已经挖了(2/3)，还剩30米，这条水渠全长是多少米．
<gadget id="calculator">2 / 3</gadget>
<output>2/3 = around 0.666667</output>

<gadget id="calculator">1 - (2/3)</gadget>
<output>1/3 = around 0.333333</output>

<gadget id="calculator">30 / (1/3)</gadget>
<output>90</output>

<result>90</result>