HP HP-20S - Display Format of Numbers

Two-Number Functions. When a function requires two numbers,
the numbers are entered like this: numberl number2. Pressing
evaluates the current expression and displays :. For example,
the following keystrokes calculate the percent change between 17 and
29:
Keys: Display: Description:
17 17.0000 Enters numberl, dis-
plays : annunciator.
29 29 Enters number?2.
(«) 70.5882 Calculates the percent
change.
Calculate the number of combinations of four items taken two at a
time:
4 2 (] 6.0000 Calculates number of
combinations.
If you enter numberl, then press a two-number function key without
pressing (INPUT], the calculator supplies a zero as number2. If you enter a
number, press (INPUT], and then press a two-number function key, the cal-
culator uses the same number for both numberl and number2.
Display Format of Numbers
When you turn on the HP-20S for the first time, numbers are displayed
with four decimal places and a period as the decimal point. The display
format controls how many digits appear in the display.
16 1: Getting Started