A batch of 2400 parts, (1/3) is completed on the first day, and (1/4) is completed on the second day. What fraction of this batch of parts is left unfinished?
一批零件2400个，第一天完成它的(1/3)，第二天完成它的(1/4)．还剩下这批零件的几分之几没完成？
<gadget id="calculator">1 / 3</gadget>
<output>1/3 = around 0.333333</output>

<gadget id="calculator">1 / 4</gadget>
<output>1/4 = around 0.25</output>

<gadget id="calculator">(1/3) + (1/4)</gadget>
<output>7/12 = around 0.583333</output>

<gadget id="calculator">1 - (7/12)</gadget>
<output>5/12 = around 0.416667</output>

<result>5/12 = around 0.416667</result>