Khan Academy
Khan Academy: Add and Subtract Mixed Numbers 2 (With Regrouping)
Practice adding and subtracting mixed numbers with common (like) denominators. Some items require regrouping. Students receive immediate feedback and have the opportunity to try questions repeatedly, watch a video or receive hints.
Homeschool Math
Homeschool Math: Subtracting Mixed Numbers With Like Fractional Parts
A lesson about subtracting mixed numbers with like fractional parts using the strategies for the subtraction of regrouping and subtracting in parts (piece by piece).