Master Wang needs to process 500 parts. He processed 40% of the total number on the first day and 1/4 of the total number on the second day. How many parts are left?
王师傅要加工500个零件，第一天加工了总数的40%，第二天加工了总数的(1/4)，还剩下多少个？
<gadget id="calculator">40 / 100</gadget>
<output>2/5 = around 0.4</output>

<gadget id="calculator">1 / 4</gadget>
<output>1/4 = around 0.25</output>

<gadget id="calculator">1 - (2/5) - (1/4)</gadget>
<output>7/20 = around 0.35</output>

<gadget id="calculator">500 * (7/20)</gadget>
<output>175</output>

<result>175</result>