Master Wang processes a batch of parts, and the ratio of the number of completed parts to the total number of parts on the first day is 1:5. If you process 45 more, you can complete 40% of this batch of parts. How many parts are processed on the first day?
王师傅加工一批零件，第一天完成的个数与零件总个数的比是1：5．如果再加工45个，就可以完成这批零件的40%．第一天加工零件多少个？
<gadget id="calculator">40 / 100</gadget>
<output>2/5 = around 0.4</output>

<gadget id="calculator">1 / 5</gadget>
<output>1/5 = around 0.2</output>

<gadget id="calculator">(2/5) - (1/5)</gadget>
<output>1/5 = around 0.2</output>

<gadget id="calculator">45 / (1/5)</gadget>
<output>225</output>

<gadget id="calculator">225 * (1/5)</gadget>
<output>45</output>

<result>45</result>