The shape of an orchard is trapezoid. Its upper base is 80 meters, its lower base is 120 meters, and its height is 40 meters. If each fruit tree covers an area of 8 square meters, how many fruit trees are there in this orchard?
一个果园的形状是梯形．它的上底是80米，下底是120米，高是40米．如果每棵果树占地8平方米，这个果园共有果树多少棵？
<gadget id="calculator">80 + 120</gadget>
<output>200</output>

<gadget id="calculator">40 / 2 / 8</gadget>
<output>5/2 = around 2.5</output>

<gadget id="calculator">200 * (5/2)</gadget>
<output>500</output>

<result>500</result>