(4/7)*(5/9)/(4/7)*(5/9)=how much.
(4/7)*(5/9)/(4/7)*(5/9)=多少．
<gadget id="calculator">4 / 7</gadget>
<output>4/7 = around 0.571429</output>

<gadget id="calculator">5 / 9</gadget>
<output>5/9 = around 0.555556</output>

<gadget id="calculator">(5/9) / (4/7)</gadget>
<output>35/36 = around 0.972222</output>

<gadget id="calculator">(4/7) * (35/36) * (5/9)</gadget>
<output>25/81 = around 0.308642</output>

<result>25/81 = around 0.308642</result>