You have just about everything you need to add and subtract fractions.  This worksheet will help tie all the pieces together.  Work through the worksheet, then come back here to practice a few more problems.  There are also videos below if you need more help.

Once you finish this section, you should have a good handle on fractions, but you aren't quite done yet.  Make certain you move on to Unit 7:  Order of Operations.  Don't assume that you know order of operations, therefore you don't need to keep going.

Just like any skill you want to be good at, being proficient with fractions requires practice.  Here are some Khan Academy practice pages that will give you immediate feedback as you do practice problems.

Make certain you can work through these two sets of problems with mixed numbers.  If you are fine with these, you probably don't need to do the proper fraction problems below.  If these are tough, start with the proper fractions first.

These two practice sets are proper fractions only.  If you are able to add and subtract mixed numbers, these will be easy.

This is a video showing addition of fractions with common denominators.

This video walks through adding fractions with different denominators.

Here is a video on adding mixed numbers.