Master Li used to process a part for 5 hours, but after improving the process, it only takes 4 hours, so how much his work efficiency has improved.
李师傅原来加工一个零件用时5h，后来改进工艺后只需4h，那么他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>