These cards introduce algebra in a way that and child can understand. Believe it or not, I have used these to teach first grade students the basics of Algebra, and they absolutely love it. The first couple of sets just handle addition and subtraction, and the later sets involve multiplying dividing, and combining variables.

It's recommended that a scale be used in algebraic demonstrations, especially with younger students, since the idea of manipulating both sides of an equation can be quite foreign to them. Showing how we can add a number to each side of the scale and not change the balance of the equation is a tactile way of understanding algebra that may stick with them their entire life.