A telephone line is 15 meters long, if (2/3) is used up, how many meters are left?
一根电话线长15米，用去(2/3)，还剩下多少米？
<gadget id="calculator">2 / 3</gadget>
<output>2/3 = around 0.666667</output>

<gadget id="calculator">15 * (2/3)</gadget>
<output>10</output>

<gadget id="calculator">15 - 10</gadget>
<output>5</output>

<result>5</result>