For a 4-meter-long rope, first cut off (1/2), and then cut off (1/2) meter, how many meters are left.
4米长的绳子，先截下(1/2)，再截下(1/2)米，还剩下多少米．
<gadget id="calculator">1 / 2</gadget>
<output>1/2 = around 0.5</output>

<gadget id="calculator">4 * (1/2)</gadget>
<output>2</output>

<gadget id="calculator">4 - 2 - (1/2)</gadget>
<output>3/2 = around 1.5</output>

<result>3/2 = around 1.5</result>