Test students' understanding of how supply and demand determine prices and quantities in a simple local market (e.g., lemonade stand or school store). Assess knowledge of the laws of demand and supply, market equilibrium, how shifts in supply or demand change equilibrium price and quantity, common causes of shifts (costs, weather, tastes, substitutes), and basic interpretation of supply/demand graphs. Tasks include scenario-based predictions, conceptual calculations of direction of change, and written explanations linking causes to effects.