An approximately trapezoidal orchard has an upper base of 120m, a lower base of 180m, and a height of 60m. If each fruit tree covers an area of 15m**2, how many fruit trees are there in this orchard?
一个近似梯形的果园，量得它的上底是120m，下底是180m，高是60m．如果每棵果树占地15m**2，这个果园共有果树多少棵？
<gadget id="calculator">120 + 180</gadget>
<output>300</output>

<gadget id="calculator">60 / 2 / 15</gadget>
<output>2</output>

<gadget id="calculator">300 * 2</gadget>
<output>600</output>

<result>600</result>