(3/5)+(6/7)+(5/6)+(7/12)+(9/20)+(11/30)+(13/42).
(3/5)+(6/7)+(5/6)+(7/12)+(9/20)+(11/30)+(13/42)．
<gadget id="calculator">3 / 5</gadget>
<output>3/5 = around 0.6</output>

<gadget id="calculator">6 / 7</gadget>
<output>6/7 = around 0.857143</output>

<gadget id="calculator">5 / 6</gadget>
<output>5/6 = around 0.833333</output>

<gadget id="calculator">7 / 12</gadget>
<output>7/12 = around 0.583333</output>

<gadget id="calculator">9 / 20</gadget>
<output>9/20 = around 0.45</output>

<gadget id="calculator">11 / 30</gadget>
<output>11/30 = around 0.366667</output>

<gadget id="calculator">13 / 42</gadget>
<output>13/42 = around 0.309524</output>

<gadget id="calculator">(3/5) + (6/7) + (5/6) + (7/12) + (9/20) + (11/30) + (13/42)</gadget>
<output>4</output>

<result>4</result>