job takes 10 hours to complete alone, but now it is completed 2 hours earlier, how much the work efficiency will be improved.
一项工作，甲独做要10小时完成，现在提前2小时完成，工作效率提高多少．
<gadget id="calculator">10 - 2</gadget>
<output>8</output>

<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>