The team leader gave A and B two young workers the task of processing a box of parts each. The same number of parts per box. The ratio of A and B’s processing efficiency at the beginning is 5:4. They start working at the same time. When the total number of parts they process is exactly the number of parts in a box, A’s efficiency will decrease by 20%, and B’s efficiency will increase by 20%. , so that when A finishes processing his own box of parts, and B still has 10 unfinished parts, how many parts are there in a box of processed parts?
组长给甲、乙两名青工各一箱零件的加工任务．每箱零件数相同．甲、乙两人刚开始的加工效率之比为5：4，他们同时开始工作，当他们加工的零件总数刚好是一箱的零件数目时，甲的效率降低20%，乙的效率提高20%，这样当甲加工完自己的一箱零件时，乙还剩有10个未加工完，则所加工的一箱零件有多少个？
<gadget id="calculator">80 / 100</gadget>
<output>4/5 = around 0.8</output>

<gadget id="calculator">5 * (4/5)</gadget>
<output>4</output>

<gadget id="calculator">120 / 100</gadget>
<output>6/5 = around 1.2</output>

<gadget id="calculator">4 * (6/5)</gadget>
<output>24/5 = around 4.8</output>

<gadget id="calculator">4 / (24/5)</gadget>
<output>5/6 = around 0.833333</output>

<gadget id="calculator">(5/6) * 10</gadget>
<output>25/3 = around 8.333333</output>

<gadget id="calculator">5 / 9</gadget>
<output>5/9 = around 0.555556</output>

<gadget id="calculator">4 / 9</gadget>
<output>4/9 = around 0.444444</output>

<gadget id="calculator">(5/6) * (4/9)</gadget>
<output>10/27 = around 0.37037</output>

<gadget id="calculator">(5/9) - (10/27) - 1</gadget>
<output>-22/27 = around -0.814815</output>

<gadget id="calculator">(5/6) + (-22/27)</gadget>
<output>1/54 = around 0.018519</output>

<gadget id="calculator">(25/3) / (1/54)</gadget>
<output>450</output>

<result>450</result>