Section 5: The Display and Continuous Memory

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Digit Separators

The HP-15C is set at power-up so that it separates integral and fractional portions of a number with a period (a decimal point), and separates groups of three digits in the integer portion with a comma. You can reverse this setting to conform to the numerical convention used in many countries. To do so, turn off the calculator. Press and hold =, press and hold ., release =, then release . (= / .). (Repeating this sequence will set the calculator to the previous display convention.)

Keystrokes

Display

12345.67

12,345.67

=/ .

12.345.6700

=/ .

12,345.6700

Error Display

If you attempt an improper operation—such as division by zero—an error message (Error followed by a digit) will appear in the display. For a complete listing of error messages and their causes, refer to appendix A.

To clear the Error display and restore the calculator to its prior condition, press any key. You can then resume normal operation.

Overflow and Underflow

Overflow. When the result of a calculation in any register is a number with

amagnitude greater than 9.999999999×1099, ± 9.999999999×1099 is placed in the affected register and the overflow flag, flag 9, is set.* Flag 9 causes the display to blink. When overflow occurs in a running program, execution continues until completion of the program, and then the display blinks.

The blinking can be stopped and flag 9 cleared by pressing , = or "9.

Underflow. If the result of a calculation in any register is a number with a magnitude less than 1.000000000×10-99, that number will be replaced by zero. Underflow does not have any other effect.

* Recall that display does not include the last three digits of the mantissa.

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HP 15c Scientific manual Digit Separators, Error Display, 12.345.6700, 12,345.6700