To process a batch of materials, it was originally planned to be completed in 30 days, but it was actually completed in 25 days. How much has the work efficiency been improved?
要加工一批材料，原计划30天完成，实际只用了25天就完成了，工作效率提高了多少
<gadget id="calculator">1 / 25</gadget>
<output>1/25 = around 0.04</output>

<gadget id="calculator">1 / 30</gadget>
<output>1/30 = around 0.033333</output>

<gadget id="calculator">(1/25) - (1/30)</gadget>
<output>1/150 = around 0.006667</output>

<gadget id="calculator">(1/150) / (1/30)</gadget>
<output>1/5 = around 0.2</output>

<result>1/5 = around 0.2</result>