(4/5)*(5/7)*(7/8).
(4/5)*(5/7)*(7/8)．
<gadget id="calculator">4 / 5</gadget>
<output>4/5 = around 0.8</output>

<gadget id="calculator">5 / 7</gadget>
<output>5/7 = around 0.714286</output>

<gadget id="calculator">7 / 8</gadget>
<output>7/8 = around 0.875</output>

<gadget id="calculator">(4/5) * (5/7) * (7/8)</gadget>
<output>1/2 = around 0.5</output>

<result>1/2 = around 0.5</result>