To complete a batch of parts, it takes A to dry for 5 days, and B to dry for another 6 days, or A to dry for 7 days first, and B to dry for 2 days. If A can complete 60 parts per day, what is the total number of parts in this batch?
完成一批零件，需甲干5天，乙再干6天，或甲先干7天，乙再干2天．如果甲每天能完成60个零件，那么这批零件的总数是多少个？
<gadget id="calculator">5 * 60</gadget>
<output>300</output>

<gadget id="calculator">7 - 5</gadget>
<output>2</output>

<gadget id="calculator">6 - 2</gadget>
<output>4</output>

<gadget id="calculator">60 / 4</gadget>
<output>15</output>

<gadget id="calculator">2 * 15</gadget>
<output>30</output>

<gadget id="calculator">6 * 30</gadget>
<output>180</output>

<gadget id="calculator">300 + 180</gadget>
<output>480</output>

<result>480</result>