For the numeric types, the .NET structure names and their C# keyword equivalents are shown here:
.NET Structure NameC# Name
Decimaldecimal
Doubledouble
Singlefloat
Int16short
Int32int
Int64long
UInt16ushort
UInt32uint
UInt64ulong
Bytebyte
Sbytesbyte
The structures are defined inside the System namespace.
The fully qualified name for Int32 is System.Int32.