Calculation: (4/(1*3))-(8/(3*5))+(12/(5*7))-(16/(7*9))+(20/(9*11) )-(24/(11*13)).
计算：(4/(1*3))-(8/(3*5))+(12/(5*7))-(16/(7*9))+(20/(9*11))-(24/(11*13))．
<gadget id="calculator">1 * 3</gadget>
<output>3</output>

<gadget id="calculator">4 / 3</gadget>
<output>4/3 = around 1.333333</output>

<gadget id="calculator">3 * 5</gadget>
<output>15</output>

<gadget id="calculator">8 / 15</gadget>
<output>8/15 = around 0.533333</output>

<gadget id="calculator">(4/3) - (8/15)</gadget>
<output>4/5 = around 0.8</output>

<gadget id="calculator">5 * 7</gadget>
<output>35</output>

<gadget id="calculator">12 / 35</gadget>
<output>12/35 = around 0.342857</output>

<gadget id="calculator">7 * 9</gadget>
<output>63</output>

<gadget id="calculator">16 / 63</gadget>
<output>16/63 = around 0.253968</output>

<gadget id="calculator">(12/35) - (16/63)</gadget>
<output>4/45 = around 0.088889</output>

<gadget id="calculator">9 * 11</gadget>
<output>99</output>

<gadget id="calculator">20 / 99</gadget>
<output>20/99 = around 0.20202</output>

<gadget id="calculator">11 * 13</gadget>
<output>143</output>

<gadget id="calculator">24 / 143</gadget>
<output>24/143 = around 0.167832</output>

<gadget id="calculator">(20/99) - (24/143)</gadget>
<output>4/117 = around 0.034188</output>

<gadget id="calculator">(4/5) + (4/45) + (4/117)</gadget>
<output>12/13 = around 0.923077</output>

<result>12/13 = around 0.923077</result>