Master Li processed a batch of parts, completed the plan in the first half of the month (5/8), and completed the plan in the second half of the month (3/5). What percentage of Master Li's overfulfilled plan this month?
李师傅加工一批零件，上半月完成计划的(5/8)，下半月完成计划的(3/5)．这个月李师傅超额完成计划的几分之几？
<gadget id="calculator">3 / 5</gadget>
<output>3/5 = around 0.6</output>

<gadget id="calculator">5 / 8</gadget>
<output>5/8 = around 0.625</output>

<gadget id="calculator">(5/8) - 1</gadget>
<output>-3/8 = around -0.375</output>

<gadget id="calculator">(3/5) + (-3/8)</gadget>
<output>9/40 = around 0.225</output>

<result>9/40 = around 0.225</result>