The shape of an orchard is trapezoidal, its upper base is 120 meters, its lower base is 180 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120米，下底是180米，高是50米，如果每棵果树占地10平方米，这果园共有多少棵果树？
<gadget id="calculator">120 + 180</gadget>
<output>300</output>

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

<gadget id="calculator">300 * (5/2)</gadget>
<output>750</output>

<result>750</result>