A book has 320 pages in total. After reading (2/5) of it, how many pages are left unread?
一本书共320页，读了它的(2/5)，还剩多少页没读？
<gadget id="calculator">2 / 5</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">320 * (3/5)</gadget>
<output>192</output>

<result>192</result>