Khan Academy
Khan Academy: Pre Algebra: Adding and Simplifying Radicals
Video showing how to add and subtract radicals by first simplifying the radicals. Video is also included in the Algebra: ck12.org strand. [7:57]
Sophia Learning
Sophia: Subtracting Radical Expressions With Like Radicands
This tutorial demonstrates how to subtract like radicands. The lesson provides detailed examples and allows students to practice a few problems on their own and check answers with the video.
Khan Academy
Khan Academy: Algebra: Adding and Simplifying Radicals
Video showing how to add radicals and then simplify the results. [4:41]