Xiaohong walks from home to school, and the post office is at (8/9) of the whole journey; she walks from school to home, and the place (1/3) of the whole journey is 0.42 kilometers away from the post office. How far is Xiaohong's home from school km?
小红从家到学校，行到全程的(8/9)处是邮局；她从学校往家走，行到全程的(1/3)的地方距邮局0.42千米，小红家距学校多少千米？
<gadget id="calculator">1 / 3</gadget>
<output>1/3 = around 0.333333</output>

<gadget id="calculator">8 / 9</gadget>
<output>8/9 = around 0.888889</output>

<gadget id="calculator">1 - (8/9)</gadget>
<output>1/9 = around 0.111111</output>

<gadget id="calculator">(1/3) - (1/9)</gadget>
<output>2/9 = around 0.222222</output>

<gadget id="calculator">0.42 / (2/9)</gadget>
<output>1.89</output>

<result>1.89</result>