The engineering team dug a 600-meter cave, dug 20% of the total length in the first month, and dug the full length (1/4) in the second month. How much more can be completed?
工程队挖一条600米的山洞，第一个月挖了全长的20%，第二个月挖了全长的(1/4)，再挖多少就可以完工？
<gadget id="calculator">20 / 100</gadget>
<output>1/5 = around 0.2</output>

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

<gadget id="calculator">(1/5) + (1/4)</gadget>
<output>9/20 = around 0.45</output>

<gadget id="calculator">600 * (9/20)</gadget>
<output>270</output>

<gadget id="calculator">600 - 270</gadget>
<output>330</output>

<result>330</result>