A piece of iron wire 30 meters long, first cut off 50%, and then cut off (1/2) meter, how many meters are left.
一段长30米的铁丝，先剪去50%，再剪去(1/2)米，还剩下多少米．
<gadget id="calculator">50 / 100</gadget>
<output>1/2 = around 0.5</output>

<gadget id="calculator">30 * (1/2)</gadget>
<output>15</output>

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

<gadget id="calculator">30 - 15 - (1/2)</gadget>
<output>29/2 = around 14.5</output>

<result>29/2 = around 14.5</result>