Master Zhang planned to use one month to complete the processing tasks of a batch of parts. As a result, he completed 70% of the full-month tasks in the first half of the month, and 75% of the full-month tasks in the second half of the month. As a result, 45 parts were overfulfilled. Ask how many parts Master Zhang originally planned to process in a month?
张师傅计划利用一个月的时间完成一批零件的加工任务，结果上半月完成了全月任务的70%，下半月完成了全月任务的75%，结果超额完成了45个零件．问张师傅原计划一个月加工多少个零件？
<gadget id="calculator">70 / 100</gadget>
<output>7/10 = around 0.7</output>

<gadget id="calculator">75 / 100</gadget>
<output>3/4 = around 0.75</output>

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

<gadget id="calculator">(7/10) + (-1/4)</gadget>
<output>9/20 = around 0.45</output>

<gadget id="calculator">45 / (9/20)</gadget>
<output>100</output>

<result>100</result>