Xinchang County, Zhejiang Province is known as the "Hometown of Long-haired Rabbits". Its giant high-yielding long-haired rabbits can produce 0.821 kilograms of wool per year. Uncle Liu’s house has 4 floors of rabbit houses, with 15 rabbits on each floor. How many kilograms of rabbit hair can be produced in total every year?
浙江新昌县素有"长毛兔之乡"的美称，其巨型高产长毛兔每只年产毛量达0.821千克．刘大伯家有4层兔舍，每层15只，每年一共可以产兔毛多少千克？
<gadget id="calculator">15 * 4</gadget>
<output>60</output>

<gadget id="calculator">0.821 * 60</gadget>
<output>49.26</output>

<result>49.26</result>