A ribbon is 12 meters long, how many meters are left after (5/6) is used up?
一根丝带长12米，用去(5/6)后，还余下多少米．
<gadget id="calculator">5 / 6</gadget>
<output>5/6 = around 0.833333</output>

<gadget id="calculator">1 - (5/6)</gadget>
<output>1/6 = around 0.166667</output>

<gadget id="calculator">12 * (1/6)</gadget>
<output>2</output>

<result>2</result>