cabbage field is triangular in shape. Its base is 21 meters and its height is 18 meters. If 10 cabbages can be planted per square meter, how many cabbages can be planted in this land?
一块白菜地的形状是三角形．它的底是21米，高是18米．如果每平方米可栽白菜10棵，这块地一共可栽白菜多少棵？
<gadget id="calculator">18 / 2</gadget>
<output>9</output>

<gadget id="calculator">21 * 9 * 10</gadget>
<output>1_890</output>

<result>1_890</result>