Introduction video to subtracting fractions within 1, with plenty of practice examples.
Best video I've found on this, students can pause where they like to solve problems, and it looks at a range of fractions within 1.
Example questions and answers for fractions with the same denominator, as well as a powerpoint presentation.
Video + Worksheet that introduces adding and subtracting fractions with the same denominator, but also goes on to look at different denominators, which some students will find hard at this stage.