A pile of coal weighs 2 tons, (1/3) is used up, how much is left?
一堆煤重2吨，用去了(1/3)，还剩下几分之几？
<gadget id="calculator">1 / 3</gadget>
<output>1/3 = around 0.333333</output>

<gadget id="calculator">1 - (1/3)</gadget>
<output>2/3 = around 0.666667</output>

<result>2/3 = around 0.666667</result>