Calculation: (1/2)-(1/4)-(1/8)=how much.
计算：(1/2)-(1/4)-(1/8)=多少．
<gadget id="calculator">1 / 2</gadget>
<output>1/2 = around 0.5</output>

<gadget id="calculator">1 / 4</gadget>
<output>1/4 = around 0.25</output>

<gadget id="calculator">1 / 8</gadget>
<output>1/8 = around 0.125</output>

<gadget id="calculator">(1/2) - (1/4) - (1/8)</gadget>
<output>1/8 = around 0.125</output>

<result>1/8 = around 0.125</result>