built-in types
The following table gives the name, size, format, type suffix, and the minimum and maximum value of every built in data type. 

suf  bits  name  format  minimum value maximum value
@  8  SBYTE  signed byte integer  -128  +127
@@  8  UBYTE  unsigned byte integer  0  +255
%  16  SSHORT  signed short integer  -32768  +32767
%%  16  USHORT  unsigned short integer  0  +65535
&  32  SLONG  signed long integer  -2147483648  +2147483647
&&  32  ULONG  unsigned long integer  0  +4294967395
32/64  XLONG  natural CPU integer  MIN SLONG/GIANT  MAX SLONG/GIANT
32/64  GOADDR  GOTO address  MIN XLONG  MAX XLONG
32/64  SUBADDR  GOSUB address  MIN XLONG  MAX XLONG
32/64  FUNCADDR  function address  MIN XLONG  MAX XLONG
$$  64  GIANT  signed giant integer  -9223372036854775808  +9223372036854775807
!  32  SINGLE  IEEE floating point  -1e38  +1e38
#  64  DOUBLE  IEEE floating point  -1d308  +1d308
$  STRING  unsigned byte string  zero characters  2147483647 characters
64  SCOMPLEX  SINGLE complex  1e38 : -1e38  +1e38 : +1e38
128  DCOMPLEX  DOUBLE complex  1d308 : -1d308  +1d308 : +1d308

coersion AKA type conversion
Type conversion, also called coercion, is performed automatically when appropriate.   For example, when an operator combines two operands in expression evaluation, the smaller type is promoted to the larger type before the operation is performed.

A consistent set of intuitive, efficient intrinsics for explicit type conversion are also provided.  For all explicit type conversions, the name of the intrinsic is the name of the data type to convert to, as the following table illustrates.  The argument can be any built-in simple (numeric) or string type.

  SBYTE()     convert to SBYTE
  UBYTE()     convert to UBYTE
  SSHORT()    convert to SSHORT
  USHORT()    convert to USHORT
  SLONG()     convert to SLONG
  ULONG()     convert to ULONG
  XLONG()     convert to XLONG
  GOADDR()    convert to GOADDR
  SUBADDR()   convert to SUBADDR
  FUNCADDR()  convert to FUNCADDR
  GIANT()     convert to GIANT
  SINGLE()    convert to SINGLE
  DOUBLE()    convert to DOUBLE
  STRING()    convert to STRING
  STRING$()   convert to STRING

type sizes
XLONG, GOADDR, SUBADDR, and FUNCADDR data types are 32-bit on some CPUs and 64-bit on others.  These natural integer and address types are 64-bit if the logical address of the computer CPU is 64-bits.  This does not alter how properly written programs operate.  To assure portability, avoid writing programs that depend on the size of these data types being 32-bits or 64-bits.