Mr. Li completed a job that was originally planned to be completed in 10 days, but actually only took 8 days. How much has the work efficiency increased?
李老师完成一件工作，原计划10天完成，实际只用了8天，工作效率提高了百分之几？
<gadget id="calculator">1 / 8</gadget>
<output>1/8 = around 0.125</output>

<gadget id="calculator">1 / 10</gadget>
<output>1/10 = around 0.1</output>

<gadget id="calculator">(1/8) - (1/10)</gadget>
<output>1/40 = around 0.025</output>

<gadget id="calculator">(1/40) / (1/10)</gadget>
<output>1/4 = around 0.25</output>

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