It was originally planned to take 25 days to do a job, but it actually took 20 days. How much has the work efficiency improved?
做一件工作，原计划用25天，实际上用了20天，工作效率提高了多少
<gadget id="calculator">1 / 20</gadget>
<output>1/20 = around 0.05</output>

<gadget id="calculator">1 / 25</gadget>
<output>1/25 = around 0.04</output>

<gadget id="calculator">(1/20) - (1/25)</gadget>
<output>1/100 = around 0.01</output>

<gadget id="calculator">(1/100) / (1/25)</gadget>
<output>1/4 = around 0.25</output>

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