HP -28S Manual page 210

Decimal Point Mode
The comma and the period share the roles of radix mark (to distin-
guish the integer part of a number from the fractional part) and
separator (to distinguish objects in the command line; the space is al-
ways a separator). You can assign these roles to the comma and
period in either order.
RDX, Off ( RDX, ,Flag 48 Clear). The period is the radix mark
(decimal point), and the comma is a separator.
RDX, On ( RDX, • , Flag 48 Set).
The comma is the radix mark, and the period is a separator.
Number Format
These modes determine the number of decimal places displayed for
real numbers. The commands FIX, SCI, and ENG require a real-num-
ber argument n. The current number format mode also affects the
command RND (round).
STD Format ( SlD.).
Real numbers are displayed with a decimal
point or an exponent only if necessary.
FIX Format (
FIX- ).
Real numbers are displayed with n decimal
places. An exponent is displayed only if necessary.
SCI Format ( SCI. ). Real numbers are displayed as a mantissa,
which is less than 10 and contains n decimal places, and an exponent.
ENG Format ( ENe-).
Real numbers are displayed as a mantissa,
which contains n
+
1 digits, and an exponent that is a multiple of 3.
Integer Base
You can choose the base used for entering and displaying binary inte-
gers. The choice of base doesn't affect the internal structure of binary
integers, which are always treated as a sequence of bits.
24: Modes 209