Uncle Wang’s family has (9/10) hectares of vegetable land, and he plans to use (1/2) of it to grow peppers, (1/5) to grow eggplants, and the rest to grow tomatoes. What percentage of the total area is planted with tomatoes?
王大伯家有(9/10)公顷菜地，他准备用其中的(1/2)种辣椒，(1/5)种茄子，其余的种上西红柿．种西红柿的面积占总面积的几分之几？
<gadget id="calculator">1 / 2</gadget>
<output>1/2 = around 0.5</output>

<gadget id="calculator">1 / 5</gadget>
<output>1/5 = around 0.2</output>

<gadget id="calculator">1 - (1/2) - (1/5)</gadget>
<output>3/10 = around 0.3</output>

<result>3/10 = around 0.3</result>