The production of a batch of clothing was originally planned to be completed in 5 days. After improving the technology, it was actually completed one day earlier than the original plan. By what percentage has the actual work efficiency been improved?
生产一批服装，原计划5天完成．改进技术后，实际比原计划提前1天完成．实际工效提高了百分之几？
<gadget id="calculator">5 - 1</gadget>
<output>4</output>

<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>