                                     
                               FRAC.TXT File
                                     
                    Fraction Calculator by Dave Vomocil
                                     
                  Copyright (c) Hewlett-Packard Company.


Overview
--------

The FRAC programs can be used to turn your HP 48 into a four function RPN
machine that handles fractions graphically.  That is, you will be able
perform computations on mixed numbers the way you did in grade school.  The
application consists of the following variables in the FRAC directory:

|GCD|     Computes the Greatest Common Divisor.

|LCM|     Computes the Least Common Multiple.

|PLUS|    Adds two mixed numbers.

|SUBTR|   Subtracts two mixed numbers.

|MULTI|   Multiplys two mixed numbers.

|DIVI|    Divides two mixed numbers.

|DPLAY|   Displays a mixed number.

|SWAPR|   Swaps two mixed numbers on the stack.

In addition, these variables are used by the functions above:

DISPL     Common display code used by DPLAY, PLUS, SUBTR, etc.

ADD       Common arithmetic code used by PLUS and SUBTR.

KEYS      This is a list you can hand to STOK to assign values to your
          'user' keys.


Installation
------------

Transfer FRAC to the HP 48 and change to the FRAC directory.


Operation
---------

The software looks to the stack for arguments.  It uses three levels to
define a mixed number.  It wants the whole number in level three, the
numerator in level two, and the denominator in level one.

The operators 'PLUS', 'SUBTR', 'MULTI', 'DIVI' and 'SWAP' expect two mixed
numbers on the stack (one number in levels 1, 2, and 3 and the other in
levels 4, 5, and 6).  The arithmetic operators leave only the result on the
stack (again in levels 1, 2, and 3).

|DPLAY| graphically displays the mixed number in levels 1, 2, & 3; and
leaves the stack unchanged.


Example
-------

Press:  1 [SPC] 2 [SPC] 3 [ENTER] |DPLAY|; see one and two thirds
displayed.  Then press 4 [SPC] 5 [SPC] 6 |PLUS|; and see one and two thirds
plus four and five sixths equals six and one half.


Limitations
-----------

The whole number pat must be positive.  The software does not handle a
negative mixed number correctly.  For example, it says six and one half
plus a negative three and one half equals four.

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V 1.0 04/27/92 11:05 AM
