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
is.even                 checks if a number or vector is even
is.negative             check whether numbers of a vector are negative
is.odd                  checks if a number or vector is odd
is.positive             check whether numbers of a vector are positive
is.prim                 check whether a vector contains prime-numbers
is.real.positive        check whether numbers of a vector are real
                        positive. Real positive means, that zero is
                        included as a positive number.
is.whole                check whether a vector contains numbers with
                        decimal places
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 from 0 to 9999999
scm                     calculating the smallest common multiple of two
                        numbers
