66  Section 3: Basic Financial Functions 
 
File name: hp 12c pt_user's guide_English_HDPMF123E27  Page: 66 of 275   
Printed Date: 2005/8/1    Dimension: 14.8 cm x 21 cm 
 
Keystrokes 
(ALG mode) 
Display   
2.152004
}
 
2.15 
Keys in the date interest begins 
accruing and separates it from the 
next date entered. 
3.012004 
3.012004 
Keys in the date of the beginning of 
the first period. 
gÒ
 
15.00 
Actual number of odd days. 
~
 
16.00 
Number of odd days counted on the 
basis of a 30-day month. 
z
30
+
 
0.53 
Divides by the length of a monthly 
period to get the fractional part of n. 
36
n
 
36.53 
Adds the fractional part of n to the 
number of complete payment 
periods, then stores the result in n. 
5
gC
 
0.42 
Calculates and stores i. 
4500
$
 
4,500.00 
Stores PV. 
P
 
–135.17 
Monthly payment. 
Example 2: 
A 42-month loan of $3,950 for a used car began accruing interest 
on July 19, 2004, so that the first period began on August 1, 2004. Payments of 
$120 are made at the end of each month. Calculate the annual percentage rate 
(APR), using the actual number of odd days and simple interest for the odd period. 
Keystrokes 
(RPN mode) 
Display  
f
CLEAR
G
 
 
Clears financial registers. 
?Æ
 
 
Turns off the 
C
 indicator in the 
display, so that simple interest will be 
used for the odd period. 
7.192004
\
 
7.19 
Keys in the date interest begins 
accruing and separates it from the 
next date entered. 
8.012004 
8.012004 
Keys in the date of the beginning of 
the first period. 
gÒ
 
13.00 
Actual number of odd days. 
30
z
 
0.43 
Divides by the length of a monthly 
period to get the fractional part of n.