A triangular billboard with a base length of 20 meters and a height of 6 meters. If you want to paint the front of this billboard, use 500 grams of paint per square meter, how many kilograms of paint do you need to prepare at least?
一块三角形的广告牌，底边长20米，高6米．如果要油漆这块广告牌的正面，每平方米用油漆500克，至少需要准备多少千克油漆？
<gadget id="calculator">6 / 2</gadget>
<output>3</output>

<gadget id="calculator">500 / 1_000</gadget>
<output>1/2 = around 0.5</output>

<gadget id="calculator">20 * 3 * (1/2)</gadget>
<output>30</output>

<result>30</result>