Master Zhang processes a batch of parts, the ratio of the number completed on the first day to the rest is 1:4, if he processes 36 more parts, half of the parts in this batch can be completed. How many parts are there in this batch?
张师傅加工一批零件，第一天完成的个数与剩下的比是1：4，如果再加工36个，就可以完成这批零件的一半．这批零件有多少个？
<gadget id="calculator">1 / 2</gadget>
<output>1/2 = around 0.5</output>

<gadget id="calculator">1 + 4</gadget>
<output>5</output>

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

<gadget id="calculator">(1/2) - (1/5)</gadget>
<output>3/10 = around 0.3</output>

<gadget id="calculator">36 / (3/10)</gadget>
<output>120</output>

<result>120</result>