1-(1/7)=how much.
1-(1/7)=多少．
<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>