A wire is 12 meters, (1/3) is used to install the lamp, how many meters are left
一根电线12米，装电灯用去(1/3)，后还剩多少米
<gadget id="calculator">1 / 3</gadget>
<output>1/3 = around 0.333333</output>

<gadget id="calculator">12 * (1/3)</gadget>
<output>4</output>

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

<result>8</result>