Wang Ling typed a manuscript and planned to finish it in 5 hours, but actually finished it in 4 hours. How much has her work efficiency improved?
王玲打一篇文稿，计划5小时完成，实际4小时就完成了，她的工作效率提高了多少
<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>