Uncle Wang uses (8/9) of a piece of land to grow cabbage, green vegetables and potatoes, among which cabbage takes up (4/9) of this piece of land, and green vegetables take up (3/9) of this piece of land. How much of the land is planted with potatoes?
王大爷用一块地的(8/9)种白菜、青菜和土豆，其中白菜占这块地的(4/9)，青菜占这块地的(3/9)．种的土豆占这块地的多少．
<gadget id="calculator">8 / 9</gadget>
<output>8/9 = around 0.888889</output>

<gadget id="calculator">7 / 9</gadget>
<output>7/9 = around 0.777778</output>

<gadget id="calculator">(8/9) - (7/9)</gadget>
<output>1/9 = around 0.111111</output>

<result>1/9 = around 0.111111</result>