Section 5: Storing and Recalling Numbers and ALPHA Strings75
Keystrokes Display    
·   STO + ST _   · specifies the stack. The HP-41C now prompts: In which stack register?
 100.0000   The value in X, 50, is added to itself.
Storage Register Overflow
If you attempt a storage register operation that would cause the magnitude of a number in any of the storage registers to exceed 9.999999999 × 1099, the operation is not performed and the HP-41C display immediately indicates OUT OF RANGE. When you press    , the error condition is cleared and the last value in the X-register before the error is displayed. The storage registers and the stack all contains the values they held before the error-causing operation was attempted.
For example, if you store 7.33 × 1052 in R01 and attempt to use storage register arithmetic to multiply that value by 1050, the display will show OUT OF RANGE.
Keystrokes Display    
7.33  7.33 _    
EEX 52
 7.33 52
STO 01
 7.3300 52
EEX 50
 1 50
STO  ×  01  OUT OF RANGE    
To clear the overflow and return the HP-41C to the status prior to the error-causing condition, press    .
Keystrokes Display    
 1.0000 50
  Contents of X-register.
RCL 01
 7.3300 52
  Contents of R01.
Later, in section 14 of this handbook, you will learn how to tell the HP-41C to ignore these kinds of range errors.