To make a part, it was planned to be completed in 5 minutes, but it actually took 4 minutes. How much work efficiency has been improved?
做一个零件，计划5分钟做完，实际用了4分钟，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>