A rope is 12 meters long, if (2/3) of it is used up, how many meters are left?
一条绳子长12米，用去它的(2/3)，还剩多少米．
<gadget id="calculator">2 / 3</gadget>
<output>2/3 = around 0.666667</output>

<gadget id="calculator">12 * (2/3)</gadget>
<output>8</output>

<gadget id="calculator">12 - 8</gadget>
<output>4</output>

<result>4</result>