This activity is great to be used in small groups, as independent or as a partner activity. Students can use manipulatives (unifix cubes) to see that switching the order of numbers in a number sentence does not change the sum. I usually pre-bag the cubes with matching colored pencils to assist the visual learners.
To use students will need unifix cubes. Students then build a two color train with the cubes keeping same colors together. Students write a number sentence to match the train and draw the matching picture. Then students will flip the cubes and write the corresponding number sentence.