A real estate company built 550 commercial houses, and planned to cap it off in 10 months, but actually only took 8 months. How much has the actual work efficiency improved?
某房地产商建筑商品房550间，计划10个月封顶，实际只用了8个月，实际工作效率提高了多少
<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>