Master Wang needs to produce 400 parts, and 95% of the total has been completed. In order to exceed the production by 20%, how many parts still need to be processed?
王师傅要生产400个零件，已经完成了总数的95%，为了超产20%，还需要加工多少个零件？
<gadget id="calculator">20 / 100</gadget>
<output>1/5 = around 0.2</output>

<gadget id="calculator">95 / 100</gadget>
<output>19/20 = around 0.95</output>

<gadget id="calculator">(1/5) - (19/20)</gadget>
<output>-3/4 = around -0.75</output>

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

<gadget id="calculator">400 * (1/4)</gadget>
<output>100</output>

<result>100</result>