A vegetable field covers an area of 20 hectares, of which (2/5) is planted with eggplants, (1/4) is planted with potatoes, how many hectares are planted in total of eggplants and potatoes?
一片菜地占地20公顷，其中的(2/5)种茄子，(1/4)种土豆，茄子和土豆一共种了多少公顷？
<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">(2/5) + (1/4)</gadget>
<output>13/20 = around 0.65</output>

<gadget id="calculator">20 * (13/20)</gadget>
<output>13</output>

<result>13</result>