What is the quotient of the sum of (1/5) and (1/4) divided by the difference between 1 and (4/5)?
(1/5)与(1/4)的和除以1与(4/5)的差，商是多少？
<gadget id="calculator">1 / 5</gadget>
<output>1/5 = around 0.2</output>

<gadget id="calculator">1 / 4</gadget>
<output>1/4 = around 0.25</output>

<gadget id="calculator">(1/5) + (1/4)</gadget>
<output>9/20 = around 0.45</output>

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

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

<gadget id="calculator">(9/20) / (1/5)</gadget>
<output>9/4 = around 2.25</output>

<result>9/4 = around 2.25</result>