(1-(1/3))*(1-(1/5))*(1-(1/7))*(1-(1/9))*(1-(1/11))* (1-(1/13))*(1-(1/15))=how much.
(1-(1/3))*(1-(1/5))*(1-(1/7))*(1-(1/9))*(1-(1/11))*(1-(1/13))*(1-(1/15))=多少．
<gadget id="calculator">1 / 3</gadget>
<output>1/3 = around 0.333333</output>

<gadget id="calculator">1 - (1/3)</gadget>
<output>2/3 = around 0.666667</output>

<gadget id="calculator">1 / 5</gadget>
<output>1/5 = around 0.2</output>

<gadget id="calculator">1 - (1/5)</gadget>
<output>4/5 = around 0.8</output>

<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>

<gadget id="calculator">1 / 9</gadget>
<output>1/9 = around 0.111111</output>

<gadget id="calculator">1 - (1/9)</gadget>
<output>8/9 = around 0.888889</output>

<gadget id="calculator">1 / 11</gadget>
<output>1/11 = around 0.090909</output>

<gadget id="calculator">1 - (1/11)</gadget>
<output>10/11 = around 0.909091</output>

<gadget id="calculator">1 / 13</gadget>
<output>1/13 = around 0.076923</output>

<gadget id="calculator">1 - (1/13)</gadget>
<output>12/13 = around 0.923077</output>

<gadget id="calculator">1 / 15</gadget>
<output>1/15 = around 0.066667</output>

<gadget id="calculator">1 - (1/15)</gadget>
<output>14/15 = around 0.933333</output>

<gadget id="calculator">(2/3) * (4/5) * (6/7) * (8/9) * (10/11) * (12/13) * (14/15)</gadget>
<output>2_048/6_435 = around 0.31826</output>

<result>2_048/6_435 = around 0.31826</result>