Simple calculation: (1/(3*4))+(1/(4*5))+(1/(5*6))+(1/(6*7))+(1/(7*8 ))=
简便运算：(1/(3*4))+(1/(4*5))+(1/(5*6))+(1/(6*7))+(1/(7*8))=
<gadget id="calculator">3 * 4</gadget>
<output>12</output>

<gadget id="calculator">1 / 12</gadget>
<output>1/12 = around 0.083333</output>

<gadget id="calculator">4 * 5</gadget>
<output>20</output>

<gadget id="calculator">1 / 20</gadget>
<output>1/20 = around 0.05</output>

<gadget id="calculator">5 * 6</gadget>
<output>30</output>

<gadget id="calculator">1 / 30</gadget>
<output>1/30 = around 0.033333</output>

<gadget id="calculator">6 * 7</gadget>
<output>42</output>

<gadget id="calculator">1 / 42</gadget>
<output>1/42 = around 0.02381</output>

<gadget id="calculator">7 * 8</gadget>
<output>56</output>

<gadget id="calculator">1 / 56</gadget>
<output>1/56 = around 0.017857</output>

<gadget id="calculator">(1/12) + (1/20) + (1/30) + (1/42) + (1/56)</gadget>
<output>5/24 = around 0.208333</output>

<result>5/24 = around 0.208333</result>