A factory completed (2/5), (1/3), and (3/8) of the plan for this quarter in each month in the first quarter of last year, and by what percentage did it overfulfill the plan for the first quarter?
某厂去年第一季度各月分别完成本季度计划的(2/5)、(1/3)、(3/8)，超额完成第一季度计划的几分之几？
<gadget id="calculator">2 / 5</gadget>
<output>2/5 = around 0.4</output>

<gadget id="calculator">1 / 3</gadget>
<output>1/3 = around 0.333333</output>

<gadget id="calculator">3 / 8</gadget>
<output>3/8 = around 0.375</output>

<gadget id="calculator">(3/8) - 1</gadget>
<output>-5/8 = around -0.625</output>

<gadget id="calculator">(2/5) + (1/3) + (-5/8)</gadget>
<output>13/120 = around 0.108333</output>

<result>13/120 = around 0.108333</result>