In a cup of sugar water, sugar accounts for (1/7), and water accounts for ((())/(())).
一杯糖水，糖占(1/7)，水占糖水的((())/(()))．
<gadget id="calculator">1 / 7</gadget>
<output>1/7 = around 0.142857</output>

<gadget id="calculator">1 - (1/7)</gadget>
<output>6/7 = around 0.857143</output>

<result>6/7 = around 0.857143</result>