The Algebra Tiles would be a nice tool to have students explore the distributive property. I like the way it is set up because it leads to students begin thinking about how things are factored, which can be hard for students to understand
Solve simple linear equations using a balance beam representation.
I like both of the balance scales. I really like how they have one that involves negatives while the other does not. Students have a hard time understanding how negative numbers fit into solving equations and I think this could help them. I might use this is the launch for a discussion amoung the students