A rope is 3 meters long, first use up (1/2) of it, and then use up (1/2) meter, how many meters are left.
一根绳长3米，先用去它的(1/2)，再用去(1/2)米，还剩下多少米米．
<gadget id="calculator">1 / 2</gadget>
<output>1/2 = around 0.5</output>

<gadget id="calculator">1 - (1/2)</gadget>
<output>1/2 = around 0.5</output>

<gadget id="calculator">3 * (1/2)</gadget>
<output>3/2 = around 1.5</output>

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

<result>1</result>