Calculation: (1/(2*4))+(1/(4*6))+(1/(6*8))+...+(1/(88*90))=how much.
计算：(1/(2*4))+(1/(4*6))+(1/(6*8))+…+(1/(88*90))=多少．
<gadget id="calculator">1 / 4</gadget>
<output>1/4 = around 0.25</output>

<gadget id="calculator">44 / 45</gadget>
<output>44/45 = around 0.977778</output>

<gadget id="calculator">(1/4) * (44/45)</gadget>
<output>11/45 = around 0.244444</output>

<result>11/45 = around 0.244444</result>