To paint the front and back of a trapezoidal billboard. It is known that the upper bottom of this billboard is 4 meters long, the lower bottom is 5 meters long, and the height is half of the upper bottom. If 0.6 kilograms of paint is used per square meter, how many kilograms of paint are needed in total?
要为一个梯形广告牌的正反两面刷油漆．已知这个广告牌上底长4米，下底长5米，高是上底的一半．如果每平方米用油漆0.6千克，共需要油漆多少千克？
<gadget id="calculator">4 + 5</gadget>
<output>9</output>

<gadget id="calculator">4 / 2</gadget>
<output>2</output>

<gadget id="calculator">2 / 2</gadget>
<output>1</output>

<gadget id="calculator">9 * 1 * 2 * 0.6</gadget>
<output>10.8</output>

<result>10.8</result>