Important note:  The  keys  of  the  HP  12C  calculator  have  been  assigned  multiple functions. Keys are assigned white, orange and blue color codes. To enable the  white coded function, just press the desired key. For the orange coded function, press the key  at  the  bottom  of  the  calculator  followed  by  the  desired  key.  For  the  blue coded function, press the key at the bottom of the calculator followed by the desired key. In this guide, all keys are referred to by their white coded function, as they are easier to read and easier to identify.

Before you start using the calculator, you may want to perform a system reset using the following procedure.
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The  following  is  a  list  of  the  basic  preliminary  set  up  features  of  your  hp12c.  You should understand these keystrokes before you begin work on statistical or Time Value of Money (TVM) functions.
 
Please  note  that  your  calculator’s  sign  convention  requires  that  one  of  the  TVM  inputs ([PV], [FV], or [PMT]) be a negative number. Intuitively, this negative value represents the cash outflow that will occur in a TVM problem.

1. To set the number of decimal places that show in your HP12C display screen:

< f > {Desired # of decimal places}
For the exam, I would make sure that the number of decimal places is set to 5.

2. To switch between annuity-due [BEGIN] and ordinary annuity modes:

To switch to the begin mode, enter  [7] (The word BEGIN will be displayed at the bottom of the display screen.)

To switch back to the ordinary annuity mode, enter   [8] (The word BEGIN will disappear from the display screen.)

3. Clearing the HP12C screen:

To clear the calculator screen, press [CLX]

4. To clear the HP12C time value of money memory registers:

< f >  [x⇔y] (This is the key to the left of the white [CLX] key in the second row
from below.)

This function clears all entries in the time value of money functions (n, i, PV, PMT
and FV). This function is important because each TVM function button represents a
memory register. If you do not clear your memory you many have erroneous data left
over when you perform new TVM computations. Pressing the [CLX] key clears the
screen only. It does not clear the memory registers for the TVM functions, so please
be careful.

5. Clearing your work from the statistical data entry registers:

To  clear  the  single  value  and  (X,  Y)  coordinate  pairs  from  the  statistical  memory
registers, press:  < f > ! [SST]

6. Additional HP12C memory registers:

HP  12C  provides  20  additional  memory  registers  for  data  storage.  These  are numbered 0 to 9 for the first ten, and .0 to .9 for the last ten registers (yes that is a period before 0 and 9!). To enter data into a memory register press {Desired value}  [STO]  [Any memory register number, 0 to .9]

Example: Store the number 125 in the memory register .8  
125 [STO]  [.8] will do the job.
 
To recall a stored value, press
 
[RCL]  [Desired memory register number]
 
In the above example, to recall the stored value 125, press
 
[RCL] [.8] (This will display 125 on the screen.)
 
To clear all memory registers press
 
< f > [CLX] (This will clear all memory registers as well as the TVM registers.)