It is known that the mass of the 81 moon is as heavy as that of the earth. What fraction of the mass of the moon is the earth?
已知81个月球的质量才和地球一样重，月球的质量是地球的几分之几？
<gadget id="calculator">1 / 81</gadget>
<output>1/81 = around 0.012346</output>

<result>1/81 = around 0.012346</result>