Calculation: (2/(1*(1+2)))+(3/((1+2)*(1+2+3)))+(4/((1+2+3)*(1 +2+3+4)))+...+(11/((1+2+...+9+10)*(1+2+...+10+11))).
计算：(2/(1*(1+2)))+(3/((1+2)*(1+2+3)))+(4/((1+2+3)*(1+2+3+4)))+…+(11/((1+2+…+9+10)*(1+2+…+10+11)))．
<gadget id="calculator">1 / 66</gadget>
<output>1/66 = around 0.015152</output>

<gadget id="calculator">1 - (1/66)</gadget>
<output>65/66 = around 0.984848</output>

<result>65/66 = around 0.984848</result>