What’s the relationship between CaCO3 content and ash content.

What’s the relationship between CaCO3 content and ash content.

To test CaCO3 content we need to use calcining method.
In CPE, only CaCO3 can not be burned because it is inorganic material. After calcining CaCO3 is left as CaO and CaO is the ash.
Molecular weight of CaO is only 56% of CaCO3, so if we want know the CaCO3 content, then use CaO weight divide 0.56.