A truckload of cement weighs (1/2) ton, if (1/3) is used up, how much of this truckload of cement is left.
一车水泥重(1/2)吨，如果用去(1/3)，则还剩这车水泥的多少．
<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>