Khan Academy
Khan Academy: Algebra Ii: Manipulate Formulas
Manipulate multi-variable formulas to isolate specific variables in order to solve some word problems. Students receive immediate feedback and have the opportunity to try questions repeatedly, watch a video, or receive hints.
PBS
Pbs: Mike and Padhu: Bikes and Trikes
Solve a word problem with Mike and Padhu. This video focuses on valid methods of problem solving, including guess-and-check and modeling with manipulatives.