Attach an adapter for BigDecimal for extension methods.

[TheSquidCombatant]

It is assumed that it is possible to add extension methods for BigDecimal by converting BigDecimal to BigInteger and reusing extension methods for BigInteger.

We should check what is currently available on the BigDecimal data type in C#, see how other libraries work with it.

If there is nothing suitable, then, perhaps, implement the BigDecimal data type yourself. And add implementations of mathematical methods to this class.

[TheSquidCombatant]

If you have to release the BigDecimal type yourself, I suggest the following. Store it in memory as a structure with fields: uint field for the number of decimal places after the decimal point, and BigInteger field for storing the value itself and its sign. In binary form, first serialize 4 bytes of the uint field, then the BigInteger as is. In text form, serialize as a number with the number of decimal places equal to uint field value, even if this results in writing insignificant zeros.

[TheSquidCombatant]

If you have to release the BigDecimal type yourself, it is worth to put this type in namespace TheSquid.Numerics, do it in a separate repository TheSquid.Numerics and release as a separate assembly, which can be used in the assembly TheSquid.Numerics.Extensions.