A rope is (8/9) meters long, cut off (1/4) meters, how many meters are left.
一根绳子长(8/9)米，截下(1/4)米，还剩多少米．
<gadget id="calculator">8 / 9</gadget>
<output>8/9 = around 0.888889</output>

<gadget id="calculator">1 / 4</gadget>
<output>1/4 = around 0.25</output>

<gadget id="calculator">(8/9) - (1/4)</gadget>
<output>23/36 = around 0.638889</output>

<result>23/36 = around 0.638889</result>