Program:	BIGNUM (also includes LISTRING, SUBBIG1, SUBBIG2, and SUBBIG3)
Author:		Rob Gaebler
Date:		1/14/02

BIGNUM performs the four basic arithmetic operations (addition, subtraction,
multiplication, and division), as well as exponentiation, for arbitrarily large
numbers.  The reason this program can be useful is that ordinarily the TI-83
only keeps track of the 14 most significant digits of any number.  For each
operation, input two base 10 numbers.  The input numbers are actually strings,
so make sure they are only strings of digits, with no other characters.  For
each operation, the output is either a list or a string.  For example, if you
multiply 10005312458869 by 200554891, the answer can be displayed as either
{2 0 0 66143 4960941 427 8279} or "2006614349609414278279."  Obviously the
second answer looks nicer.  Unfortunately, the program computes the answer as a
list, and it takes a long time to convert the lilst to a string, so it is
usually better to display the answer as a list.