Four people, A, B, C, and D, process a batch of parts. A’s processing accounts for (1/2) of the other three’s total processing, B’s processing accounts for the other three’s processing (1/3), and C’s processing is other parts. For three people (1/5), the remaining 30 parts are processed by Ding. How many parts are there in total?
甲、乙、丙、丁四人加工一批零件，甲加工的占其他三人加工总数的(1/2)，乙加工的占其他三人加工的(1/3)，丙加工的是其他三人的(1/5)，剩下的30个零件由丁加工完成，这批零件一共有多少个？
<gadget id="calculator">1 + 2</gadget>
<output>3</output>

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

<gadget id="calculator">1 + 3</gadget>
<output>4</output>

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

<gadget id="calculator">1 + 5</gadget>
<output>6</output>

<gadget id="calculator">1 / 6</gadget>
<output>1/6 = around 0.166667</output>

<gadget id="calculator">1 - (1/3) - (1/4) - (1/6)</gadget>
<output>1/4 = around 0.25</output>

<gadget id="calculator">30 / (1/4)</gadget>
<output>120</output>

<result>120</result>