Oswego City School District
Regents Exam Prep Center: Adding and Subtracting Fractions
Use this site to learn how to add and subtract algebraic fractions, even if there aren't common denominators. Provides plenty of examples.
BBC
Bb Ci: Operations With Fractions Review
This BBC test prep review ("revision") section includes reminders and practice in adding, subtracting, multiplying, and dividing fractions. Clicking "Test Bite" on the last page will get you a short interactive quiz over the material.
Sophia Learning
Sophia: Adding Mixed Numbers
This video tutorial reviews how to add mixed numbers with like and unlike denominators. The lesson includes detailed examples.