Adding 3 numbers together can be tricky for first graders. Here is a fun, engaging way for students to practice this common core skill either in a center or independent practice. The best part it, it's self-checking! Immediate feedback to the student. Students simply complete addition problem, then check their answer using any QR Code reader. So much fun! My students can't get enough. If you like this free one, you get double the amount of cards in the paid version.