rope is (8/9) meters long, (1/4) of the total length is used up for the first time, and (1/4) meters is used up for the second time, how many meters are left?
一根绳子长(8/9)米，第一次用去全长的(1/4)，第二次用去(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>2/9 = around 0.222222</output>

<gadget id="calculator">(8/9) - (2/9) - (1/4)</gadget>
<output>5/12 = around 0.416667</output>

<result>5/12 = around 0.416667</result>