For a 3-meter-long rope, first cut off (1/2), and then cut off (1/2), how many meters are left.
3米长的绳子，先截下(1/2)，再截下(1/2)，还剩多少米米．
<gadget id="calculator">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 - (3/2)</gadget>
<output>3/2 = around 1.5</output>

<gadget id="calculator">(3/2) * (1/2)</gadget>
<output>3/4 = around 0.75</output>

<gadget id="calculator">3 - (3/2) - (3/4)</gadget>
<output>3/4 = around 0.75</output>

<result>3/4 = around 0.75</result>