Section 1: Getting Started  21 
 
File name: HP 12c Pt Converted_user's guide_English_HDP0F123E02_080207  Page: 11 of 281   
Printed Date:  {  2007/8/2Dimension: 14.8 cm x 21 cm 
 
Simple Arithmetic Calculations in RPN Mode 
In RPN mode, any simple arithmetic calculation involves two numbers and an 
operation — addition, subtraction, multiplication, or division. To do such a 
calculation on your hp 12c platinum, you first tell the calculator the two numbers, 
then tell the calculator the operation to be performed. The answer is calculated 
when the operation key (
+
,
-
,
§
, or 
z
) is pressed. 
The two numbers should be keyed into the calculator in the order they would 
appear if the calculation were written down on paper left-to-right. After keying in 
the first number, press the 
\
 key to tell the calculator that you have completed 
entering the number. Pressing 
\
  separates the second number to be entered 
from the first number already entered. 
In summary, to perform an arithmetic operation: 
1.  Key in the first number. 
2. Press \ to separate the second number from the first. 
3.  Key in the second number. 
4. Press +,-,§, or z to perform the desired operation. 
For example to calculate 13 ÷ 2, proceed as follows: 
Keystrokes 
(RPN mode) 
Display 
 
13 
13. 
Keys the first number into the 
calculator. 
\
 
13.00 
Pressing 
\
 separates the second 
number from the first. 
2 
2. 
Keys the second number into the 
calculator. 
z
 
6.50 
Pressing the operation key calculates 
the answer. 
Notice that after you pressed 
\
, two zeroes appeared following the decimal 
point. This is nothing magical: the calculator’s display is currently set to show two 
decimal places of every number that has been entered or calculated. Before you 
pressed 
\
, the calculator had no way of knowing that you had completed 
entering the number, and so displayed only the digits you had keyed in. Pressing 
\
 tells the calculator that you have completed entering the number: it terminates 
digit entry. You need not press 
\
 after keying in the second number because 
the 
+
,
-
,
§
 and 
z
 keys also terminate digit entry. (In fact, all keys terminate 
digit entry except for digit entry keys — digit keys, 
.
, 
Þ
, and 
Æ
 — and 
prefix keys — 
f
, 
g
, 
?
, 
:
, and 
(
.)