It takes Xiao Ming 4 hours and Xiao Hua 5 hours to complete a task. How much faster is Xiao Ming's efficiency than Xiao Hua's.
完成一项任务，小明要4小时，小华要5小时，小明的效率比小华的效率快多少．
<gadget id="calculator">1 / 4</gadget>
<output>1/4 = around 0.25</output>

<gadget id="calculator">1 / 5</gadget>
<output>1/5 = around 0.2</output>

<gadget id="calculator">(1/4) - (1/5)</gadget>
<output>1/20 = around 0.05</output>

<gadget id="calculator">(1/20) / (1/5)</gadget>
<output>1/4 = around 0.25</output>

<result>1/4 = around 0.25</result>