(4/(5*9))+(4/(9*13))+(4/(13*17))+(4/(17*21))+(4/(21*25))+ (4/(25*29))+(4/(29*33)).
(4/(5*9))+(4/(9*13))+(4/(13*17))+(4/(17*21))+(4/(21*25))+(4/(25*29))+(4/(29*33))．
<gadget id="calculator">5 * 9</gadget>
<output>45</output>

<gadget id="calculator">4 / 45</gadget>
<output>4/45 = around 0.088889</output>

<gadget id="calculator">9 * 13</gadget>
<output>117</output>

<gadget id="calculator">4 / 117</gadget>
<output>4/117 = around 0.034188</output>

<gadget id="calculator">13 * 17</gadget>
<output>221</output>

<gadget id="calculator">4 / 221</gadget>
<output>4/221 = around 0.0181</output>

<gadget id="calculator">17 * 21</gadget>
<output>357</output>

<gadget id="calculator">4 / 357</gadget>
<output>4/357 = around 0.011204</output>

<gadget id="calculator">21 * 25</gadget>
<output>525</output>

<gadget id="calculator">4 / 525</gadget>
<output>4/525 = around 0.007619</output>

<gadget id="calculator">25 * 29</gadget>
<output>725</output>

<gadget id="calculator">4 / 725</gadget>
<output>4/725 = around 0.005517</output>

<gadget id="calculator">29 * 33</gadget>
<output>957</output>

<gadget id="calculator">4 / 957</gadget>
<output>4/957 = around 0.00418</output>

<gadget id="calculator">(4/45) + (4/117) + (4/221) + (4/357) + (4/525) + (4/725) + (4/957)</gadget>
<output>28/165 = around 0.169697</output>

<result>28/165 = around 0.169697</result>