Calculation: ((1/5)+(1/7)+(1/9)+(1/11))*((1/7)+(1/9)+(1/11)+(1/ 13))-((1/5)+(1/7)+(1/9)+(1/11)+(1/13))*((1/7)+(1/9)+( 1/11)).
计算：((1/5)+(1/7)+(1/9)+(1/11))*((1/7)+(1/9)+(1/11)+(1/13))-((1/5)+(1/7)+(1/9)+(1/11)+(1/13))*((1/7)+(1/9)+(1/11))．
<gadget id="calculator">5 / 1</gadget>
<output>5</output>

<gadget id="calculator">7 / 1</gadget>
<output>7</output>

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

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

<gadget id="calculator">5 + 7 + 9 + 11</gadget>
<output>32</output>

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

<gadget id="calculator">7 + 9 + 11 + 13</gadget>
<output>40</output>

<gadget id="calculator">32 * 40</gadget>
<output>1_280</output>

<gadget id="calculator">5 + 7 + 9 + 11 + 13</gadget>
<output>45</output>

<gadget id="calculator">7 + 9 + 11</gadget>
<output>27</output>

<gadget id="calculator">45 * 27</gadget>
<output>1_215</output>

<gadget id="calculator">1_280 - 1_215</gadget>
<output>65</output>

<gadget id="calculator">1 / 65</gadget>
<output>1/65 = around 0.015385</output>

<result>1/65 = around 0.015385</result>