(5/(1*2))+(5/(2*3))+(5/(3*4))+…+(5/(48*49))+(5/(49*50) ) = how much.
(5/(1*2))+(5/(2*3))+(5/(3*4))+…+(5/(48*49))+(5/(49*50))=多少．
<gadget id="calculator">1 / 50</gadget>
<output>1/50 = around 0.02</output>

<gadget id="calculator">1 - (1/50)</gadget>
<output>49/50 = around 0.98</output>

<gadget id="calculator">5 * (49/50)</gadget>
<output>49/10 = around 4.9</output>

<result>49/10 = around 4.9</result>