A pool has been filled with (7/10) of water, how much water will be filled to be full.
一个水池已经灌了(7/10)的水，还要灌多少的水才满．
<gadget id="calculator">7 / 10</gadget>
<output>7/10 = around 0.7</output>

<gadget id="calculator">1 - (7/10)</gadget>
<output>3/10 = around 0.3</output>

<result>3/10 = around 0.3</result>