(1-328/(328*2.5))/1.2.
(1-328/(328*2.5))/1.2．
<gadget id="calculator">328 * 2.5</gadget>
<output>820</output>

<gadget id="calculator">328 / 820</gadget>
<output>2/5 = around 0.4</output>

<gadget id="calculator">1 - (2/5)</gadget>
<output>3/5 = around 0.6</output>

<gadget id="calculator">(3/5) / 1.2</gadget>
<output>0.5</output>

<result>0.5</result>