A trapezoidal nursery, the upper base is 84 meters, the lower base is 56 meters, and the height is 60 meters. If each tree covers an area of 3 square meters, how many trees can be planted in this nursery?
一块梯形苗圃，上底84米，下底56米，高60米．如果每棵树占地3平方米，这块苗圃一共能种多少棵树？
<gadget id="calculator">84 + 56</gadget>
<output>140</output>

<gadget id="calculator">60 / 2 / 3</gadget>
<output>10</output>

<gadget id="calculator">140 * 10</gadget>
<output>1_400</output>

<result>1_400</result>