Haimen Village builds an 80m long flood control dam (as shown in the picture). The cross section is a trapezoid, the upper base is 4m wide, the lower base is 26m wide, and the height is 5m. How many cubic meters of earth and stone are needed to build this flood control dam?
海门村修筑一条长80m的防洪堤坝(如图)，横截面是一个梯形，上底宽4m，下底宽26m，高5m，筑这条防洪堤坝需土石多少立方米？
<gadget id="calculator">4 + 26</gadget>
<output>30</output>

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

<gadget id="calculator">30 * (5/2) * 80</gadget>
<output>6_000</output>

<result>6_000</result>