Need ideas for the Associative Property? This activity is great for introducing the Associative Property to students! This reproducible train may be customized to fit the needs of your classroom. Students place counters on the compartments inside each cart and practice writing equations to show how many carts (sets of 2 groups of 5) are on the train. Easily adjust the numbers in the equation by adding counters or taking them away. This activity also makes a creative hall display for student work. BONUS: Homework or activity sheet to practice the Associative Property included.