What fraction is the difference between (4/5) and (1/4) of their sum?
(4/5)与(1/4)的差是它们和的几分之几？
<gadget id="calculator">4 / 5</gadget>
<output>4/5 = around 0.8</output>

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

<gadget id="calculator">(4/5) - (1/4)</gadget>
<output>11/20 = around 0.55</output>

<gadget id="calculator">(4/5) + (1/4)</gadget>
<output>21/20 = around 1.05</output>

<gadget id="calculator">(11/20) / (21/20)</gadget>
<output>11/21 = around 0.52381</output>

<result>11/21 = around 0.52381</result>