HP 12C Platinum Instruction Manual page 2

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HP 12C Platinum Using Memories to Solve Problems
Constant memory and planning
Because of the HP12C Platinum Constant Memory feature, any current computations may be stopped at any moment for
later resumption without any data loss. In the HP12C Platinum, memory is organized as a set of registers, where each
register can hold a number representation of any positive or negative value with a 10-digit mantissa and a two-digit
integer, positive or negative exponent of ten. When writing programs, part of these registers may also be converted to
seven program steps each.
Using register contents
Most of these registers can be directly addressed anytime it is necessary, provided that the register is available. Special
care must be taken in regard to make sure that the chosen register isn't being used for other purposes. As a general
rule, two basic operations can always be performed over existing register contents: storing and retrieving (or recalling)
numbers.
Assuming that the display contains a value to be stored, and that the storage location (register name) is already defined,
the keystroke sequence below may be performed to store the information: ? [key]. To retrieve the information stored
in one of the registers back to the display and use it in further calculations, it is necessary to use the following keystroke
sequence: : [key].
In both sequences, [key] refers to any valid keystroke sequence that defines the location (which register) where the
information in the display will be stored in or retrieved from. The valid keys for these registers are:
0 to 9
.0 to .9
w , ¼ , $ , P and M
Example 1: The index for conversion between American Dollars and Euros is stipulated as 1.00 Euro = US$1.19.
Which keystroke sequence stores this index in register R
Solution: The complete sequence for typing the index in and storing its value in register R
1.19 ?1
The image in Figure 1 shows the display contents after the keystroke sequence is executed.
Understanding register arithmetic
Along with storing and retrieval, the five lower-numbered registers ( 0 through 4 ) allow storage arithmetic with their
contents and the display number.
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?
1
- 2 - HP 12C Platinum Using Memories to Solve Problems - Version 1.0
is:
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Figure 1