There are four small animals: chicken, duck, pigeon and sparrow. A pigeon weighs 0.6 kg; a chicken weighs 0.2 kg less than twice that of a pigeon; a duck weighs 0.5 kg more than a chicken; a sparrow weighs 0.4 kg less than a pigeon. Find the average weight of these four animals.
有鸡、鸭、鸽子、麻雀四只小动物．鸽子重0.6千克；鸡的重量比鸽子的2倍少0.2千克；鸭的重量比鸡多0.5千克；麻雀的重量比鸽子少0.4千克，求这四只动物的平均重量．
<gadget id="calculator">0.6 * 2</gadget>
<output>1.2</output>

<gadget id="calculator">1.2 - 0.2</gadget>
<output>1</output>

<gadget id="calculator">0.6 - 0.4</gadget>
<output>0.2</output>

<gadget id="calculator">0.6 + 1 + 1 + 0.5 + 0.2</gadget>
<output>3.3</output>

<gadget id="calculator">3.3 / 4</gadget>
<output>0.825</output>

<result>0.825</result>