(1-(1/(2*2)))*(1-(1/(3*3)))*…*(1-(1/(10*10))).
(1-(1/(2*2)))*(1-(1/(3*3)))*…*(1-(1/(10*10)))．
<gadget id="calculator">11 / 20</gadget>
<output>11/20 = around 0.55</output>

<result>11/20 = around 0.55</result>