cancel.fraction         cancel a fraction to the smallest numbers
decimal2fraction        convert a decimal-number into fraction
gcd                     Greatest common divisor of two numbers
is.decimal              checks if a number is decimal or integer and
                        returns TRUE for decimal
is.even                 Checks whether numbers are even.
is.negative             Check whether numbers are negative.
is.odd                  Checks whether numbers are odd.
is.positive             Check whether numbers are positive.
is.prim                 Check whether a vector contains prime numbers
is.real.positive        Check whether numbers are non-negative.
is.whole                checks if a number is decimal or integer and
                        returns FALSE for decimal
prime.factor            This function calculates the prime-factors of a
                        number
primes                  generate prime-numbers in a range from START to
                        END
primlist                A vector containing primes between 1 and
                        99,999,999
scm                     calculating the smallest common multiple of two
                        numbers
