A 3-meter-long steel, cut off (1/2), and then cut off (1/2), how many meters are left
一根3米长的钢材，截下(1/2)，再截下(1/2)，还剩多少米
<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">1 - (1/2)</gadget>
<output>1/2 = around 0.5</output>

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