Calculation: ((8+9)/(8*9))-((9+10)/(9*10))+((10+11)/(10*11))-((11+12) /(11*12))+((12+13)/(12*13)).
计算：((8+9)/(8*9))-((9+10)/(9*10))+((10+11)/(10*11))-((11+12)/(11*12))+((12+13)/(12*13))．
<gadget id="calculator">8 + 9</gadget>
<output>17</output>

<gadget id="calculator">8 * 9</gadget>
<output>72</output>

<gadget id="calculator">17 / 72</gadget>
<output>17/72 = around 0.236111</output>

<gadget id="calculator">9 + 10</gadget>
<output>19</output>

<gadget id="calculator">9 * 10</gadget>
<output>90</output>

<gadget id="calculator">19 / 90</gadget>
<output>19/90 = around 0.211111</output>

<gadget id="calculator">(17/72) - (19/90)</gadget>
<output>1/40 = around 0.025</output>

<gadget id="calculator">10 + 11</gadget>
<output>21</output>

<gadget id="calculator">10 * 11</gadget>
<output>110</output>

<gadget id="calculator">21 / 110</gadget>
<output>21/110 = around 0.190909</output>

<gadget id="calculator">11 + 12</gadget>
<output>23</output>

<gadget id="calculator">11 * 12</gadget>
<output>132</output>

<gadget id="calculator">23 / 132</gadget>
<output>23/132 = around 0.174242</output>

<gadget id="calculator">(21/110) - (23/132)</gadget>
<output>1/60 = around 0.016667</output>

<gadget id="calculator">12 + 13</gadget>
<output>25</output>

<gadget id="calculator">12 * 13</gadget>
<output>156</output>

<gadget id="calculator">25 / 156</gadget>
<output>25/156 = around 0.160256</output>

<gadget id="calculator">(1/40) + (1/60) + (25/156)</gadget>
<output>21/104 = around 0.201923</output>

<result>21/104 = around 0.201923</result>