Check these sites.
http://www.mathsisfun.com/fractions_subtraction.html
http://www.mathsisfun.com/fractions_division.html
How do you subtract fractions?
How do you divide frations?
3 answers
go on youtube they show videos on that
ADDING AND SUBTRACTING: Need a common denominator
DIVIDING: Multiply the numerator fraction by the inverse of the denominator fraction
DIVIDING: Multiply the numerator fraction by the inverse of the denominator fraction