System.Numerics

Added in .NET 4.0
link - learn.microsoft.com/en-us/dotnet/api/system.numerics?view=net-7.0

System.Numerics.Vector

This is a class

System.Numerics.BigInteger

This is a structure
Double can hold 16 bit values but BigInteger has no minimum size or maximum size
You cannot use the Math class with BigInteger

System.Numerics.Complex

This is a structure

System.Numerics.Matrix3x2

This is a structure

System.Numerics.Plane

This is a structure