This file includes 4 hands-on, QR code activities that provide 3rd and 4th grade students with practice using grams and kilograms. It includes a word problem practice, a partner activity, cut and paste sorting, and a matching activity. Each practice includes an answer key and three of the practices are self-checking. Students will enjoy practicing these activities as reinforcement or extension of metric mass instruction. Students must have access to an electronic device with a QR code scanner to complete the activities.