(20-(2/55)*1)+(19-(2/55)*2)+(18-(2/55)*3)+…+(1-(2/55)*20).
(20-(2/55)*1)+(19-(2/55)*2)+(18-(2/55)*3)+…+(1-(2/55)*20)．
<gadget id="calculator">2 / 55</gadget>
<output>2/55 = around 0.036364</output>

<gadget id="calculator">1 - (2/55)</gadget>
<output>53/55 = around 0.963636</output>

<gadget id="calculator">1 + 20</gadget>
<output>21</output>

<gadget id="calculator">1 / 2</gadget>
<output>1/2 = around 0.5</output>

<gadget id="calculator">(53/55) * 21 * 20 * (1/2)</gadget>
<output>2_226/11 = around 202.363636</output>

<result>2_226/11 = around 202.363636</result>