Determining Past Or Future Dates; Clearing The Date Arithmetic Variables - HP -18C Owner's Manual

Determining Past or Future Dates
The HP-18C can determine the date a specified number of days from
another date using the actual calendar. To calculate a date:
1. Key in the known date in the current date format and press
1iDII ·
2. Key in the number of days. If the unknown date precedes the
known date, press
~.
Press
1iDIiI .
3. Press
1mIIiI .
Example: Determining a future date. On February 9, 1987, you
purchase a 120-day option on a piece of land. Determine the expira-
tion date. Assume the date format is month/day/year.
Starting from the
MAIN
menu:
Keys:
IIIB . .
2.091987
IiDII
120
IiDIiI
Display:
DATE1=
2 .. ···09 / 1987 MO~~
Description:
Displays the
CALC
menu.
Stores DATE!.
ACTUAL DAYS= 120,00
Stores the number of
days in the future.
DATE 2 =
6/09 ..... 1987
TUE
Calculates the expiration
date.
Clearing the Date Arithmetic Variables
When the HP-18C is displaying the
CALC
menu, pressing
. 1
CLEAR ALL
I
clears DATE1, DATE2, ACTUAL DAYS, 360 DAYS, and
365 DAYS to O. The date arithmetic variables are also cleared when-
ever you press . . in the
TIME
menu.
126 8: Time, Alarms, and Date Arithmetic