(1-(1/4)*(4/5))/(8/15).
(1-(1/4)*(4/5))/(8/15)．
<gadget id="calculator">1 / 4</gadget>
<output>1/4 = around 0.25</output>

<gadget id="calculator">4 / 5</gadget>
<output>4/5 = around 0.8</output>

<gadget id="calculator">(1/4) * (4/5)</gadget>
<output>1/5 = around 0.2</output>

<gadget id="calculator">1 - (1/5)</gadget>
<output>4/5 = around 0.8</output>

<gadget id="calculator">8 / 15</gadget>
<output>8/15 = around 0.533333</output>

<gadget id="calculator">(4/5) / (8/15)</gadget>
<output>3/2 = around 1.5</output>

<result>3/2 = around 1.5</result>