A trapezoidal billboard with an upper base of 8 meters, a lower base of 10 decimeters, and a height of 4 decimeters needs to be painted on the front of the billboard. If 1 kg of paint can paint 3 square meters, how much does this billboard need? Kilograms of paint?
一块梯形的广告牌，上底8米，下底10分米，高4分米，现在需要在这块广告牌的正面刷油漆，如果1千克油漆能刷3平方米，这块广告牌需要多少千克油漆？
<gadget id="calculator">10 / 10</gadget>
<output>1</output>

<gadget id="calculator">8 + 1</gadget>
<output>9</output>

<gadget id="calculator">4 / 10 / 2 / 3</gadget>
<output>1/15 = around 0.066667</output>

<gadget id="calculator">9 * (1/15)</gadget>
<output>3/5 = around 0.6</output>

<result>3/5 = around 0.6</result>