What is the difference between the largest true fraction and the smallest true fraction when the unit of fraction is (1/9).
分数单位是(1/9)的最大真分数与最小真分数的差是多少．
<gadget id="calculator">8 / 9</gadget>
<output>8/9 = around 0.888889</output>

<gadget id="calculator">1 / 9</gadget>
<output>1/9 = around 0.111111</output>

<gadget id="calculator">(8/9) - (1/9)</gadget>
<output>7/9 = around 0.777778</output>

<result>7/9 = around 0.777778</result>