piece of land (7/8) hectares, the area of the land is planted with tomatoes (2/5), cabbage (1/4), and the rest is planted with radishes. What percentage of the area of the land is the area of radishes?
一块地(7/8)公顷，种西红柿的面积占这块地的(2/5)，白菜占(1/4)，其余的种萝卜，萝卜的面积占这块地的几分之几？
<gadget id="calculator">2 / 5</gadget>
<output>2/5 = around 0.4</output>

<gadget id="calculator">1 / 4</gadget>
<output>1/4 = around 0.25</output>

<gadget id="calculator">1 - (2/5) - (1/4)</gadget>
<output>7/20 = around 0.35</output>

<result>7/20 = around 0.35</result>