The shape of an orchard is trapezoid. Its upper base is 180 meters, its lower base is 160 meters, and its height is 50 meters. If each fruit tree covers an area of 10 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180米，下底是160米，高是50米．如果每棵果树占地10平方米，这个果园共有果树多少棵？
<gadget id="calculator">180 + 160</gadget>
<output>340</output>

<gadget id="calculator">50 / 2 / 10</gadget>
<output>5/2 = around 2.5</output>

<gadget id="calculator">340 * (5/2)</gadget>
<output>850</output>

<result>850</result>