HP -28S Manual page 31

Real numbers require no delimiters. The delimiters for other object
types are on the left-hand keyboard (see items 1 and 3).
12. Power on and off; clear command line; stop program. To
turn on the calculator, press
1
ON
I;
to turn it off, press
. 1
OFF
1 .
(OFF is
printed on the keyboard above
1
ON
I.
uPress
.1
OFF
1
n
means press the
shift key. and then press
1
ON
I.)
While the calculator is on,
ION
1
also acts as the ATTN
(attention)
key
to clear text in the command line or stop a running program. (ATTN
is printed on the keyboard below
1
ON
I.)
13. Number entry. To key in numbers, use the digit keys
[Q]
through
[[j,
1
CHS
1
(change sign),
and
1
EEX
1
(enter exponent).
Assuming you want
to use the period as the decimal point (page 36), use
[J
to separate the
integer part from the fractional part. Number entry is described on
page 39.
14. Arithmetic. The arithmetic functions are described in uO ne -
Number Functions" on page 40 and uTwo-Number Functions" on
page 41.
15. Backspace. Press
[!]
to erase the last character you typed in.
16. Menu selection, next menu row. Use the menu selection keys
to assign commands to the menu keys. For example, press
I
TRIG
1
to
select the TRIG menu. To select a different menu, press another menu
selection key.
When no menu labels are visible, the
cursor menu
is active. The opera-
tions in the cursor menu ([ill§] through
~)
are printed in white
above the menu keys. When menu labels are visible, press
GB
to se-
lect the cursor menu. To restore the previous menu, press
GB
a
second time.
A menu can contain more than one row, with up to six commands in
each row. Press
1
NEXT
1
to display the next row of the current menu.
Press
. 1
PREY
1
to display the previous row.
30 1: Getting Started
I