Master Li plans to make a batch of parts. A total of 120 parts were made in the first 3 days. At this speed, it can be finished in another 5 days. How many parts are there in total? (Solution with proportional knowledge)
李师傅计划做一批零件，前3天共做了120个，照这样的速度，再做5天就可以做完，这批零件一共有多少个？(用比例知识解)
<gadget id="calculator">120 / 3</gadget>
<output>40</output>

<gadget id="calculator">40 * 5</gadget>
<output>200</output>

<gadget id="calculator">40 * 3</gadget>
<output>120</output>

<gadget id="calculator">200 + 120</gadget>
<output>320</output>

<result>320</result>