A piece of steel is 4 meters long. After (1/4) is used up, (1/4) meter is used up. How many meters are left?
一根钢材长4米，用去(1/4)后，又用去(1/4)米，还剩多少米．
<gadget id="calculator">1 / 4</gadget>
<output>1/4 = around 0.25</output>

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

<gadget id="calculator">4 * (3/4)</gadget>
<output>3</output>

<gadget id="calculator">3 - (1/4)</gadget>
<output>11/4 = around 2.75</output>

<result>11/4 = around 2.75</result>