It is known that (5/6)=(1/2)+(1/3), (7/12)=(1/3)+(1/4), (9/20)=(1/4)+ (1/5),... Please observe the law yourself, and then use the law to calculate: 1+(1/2)-(5/6)+(7/12)-(9/20)+(11/30)-( 13/42).
已知(5/6)=(1/2)+(1/3)，(7/12)=(1/3)+(1/4)，(9/20)=(1/4)+(1/5)，…请自己观察规律，再利用规律计算：1+(1/2)-(5/6)+(7/12)-(9/20)+(11/30)-(13/42)．
<gadget id="calculator">1 / 2</gadget>
<output>1/2 = around 0.5</output>

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

<gadget id="calculator">(1/2) - (5/6)</gadget>
<output>-1/3 = around -0.333333</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">(7/12) - (9/20)</gadget>
<output>2/15 = around 0.133333</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">(11/30) - (13/42)</gadget>
<output>2/35 = around 0.057143</output>

<gadget id="calculator">1 + (-1/3) + (2/15) + (2/35)</gadget>
<output>6/7 = around 0.857143</output>

<result>6/7 = around 0.857143</result>