A telephone line is 9 meters long. (2/3) is used up, how much rice is left?
一根电话线长9米．用去了(2/3)，还剩多少米？
<gadget id="calculator">2 / 3</gadget>
<output>2/3 = around 0.666667</output>

<gadget id="calculator">1 - (2/3)</gadget>
<output>1/3 = around 0.333333</output>

<gadget id="calculator">9 * (1/3)</gadget>
<output>3</output>

<result>3</result>