236 Appendix A: RPN and the Stack
File name: hp 12c pt_user's guide_English_HDPMF123E27 Page: 236 of 275
Printed Date: 2005/8/1
Dimension: 14.8 cm x 21 cm
Keystrokes
(RPN mode)
Display
84000
84,000.
Enters base amount into displayed
X-register.
§
168,000.00
Annual sales after first year.
§
336,000.00
Annual sales after second year.
§
672,000.00
Annual sales after third year.
In the example above, the constant was repeatedly multiplied by the result of the
previous operation, which was already in the displayed X-register. In another class
of calculations with constants, the constant is multiplied by (or added to, etc.) a
new number keyed into the displayed X-register. For these calculations, you must
press
O
before keying in a new number after having pressed an operator key. If
this were not done, the stack would lift when you keyed in a new number after
pressing the operator key, and the Y-register would no longer contain the constant.
(Recall — from page 230 — that the stack does not lift when a number is keyed
into the displayed X-register after
O
is pressed.)
Example:
At Permex Pipes a certain pipe fitting is packaged in quantities of 15,
75, and 250. If the cost per fitting is $4.38, calculate the cost of each package.
*
Keystrokes
(RPN mode)
Display
4.38
\\
\
4.38
Enters constant into Y-, Z-, and
T-registers.
15
15.
Enters first quantity into displayed
X-register.
§
65.70
Cost of a package of 15.
O
75
75.
Clears display and enters second
quantity into displayed X-register.
§
328.50
Cost of a package of 75.
O
250
250.
Clears display and enters third
quantity into displayed X-register.
§
1,095.00
Cost of a package of 250.
*
You may want to compare this method of arithmetic calculations with constants to the method
using
F
described on page 91.