The cafeteria bought back a pile of coal and used it (3/5), what fraction is left?
食堂买回一堆煤，用去了(3/5)，还剩下几分之几？
<gadget id="calculator">3 / 5</gadget>
<output>3/5 = around 0.6</output>

<gadget id="calculator">1 - (3/5)</gadget>
<output>2/5 = around 0.4</output>

<result>2/5 = around 0.4</result>