Algebraic expressions with coins – collecting like terms

MathematicsAlgebraAges 12–13

Drag coins worth x, y, x², xy and 1 into the tray; coins of the same kind stack into one pile, showing directly how like terms combine into a simplified expression. The Negatives screen adds "debt" coins so you can see a positive–negative pair of the same kind cancel out. The Explore screen uses coefficients for all 5 coin types and evaluates the expression for chosen values of x and y, while the Game screen has 4 levels in which you set the coefficient of each coin type to match a target expression. Adapted from the "Expression Exchange" simulation by PhET Interactive Simulations, University of Colorado Boulder (CC BY 4.0); rewritten.

Lesson: Algebraic expressions, simplifying and collecting like terms