This set of 20 task cards are aligned with common core standard 6.NS.3, adding and subtracting multi-decimal problems. Students will LOVE solving these task cards because they are geared for the 21st century, using QR codes for the problems. Students will scan each QR code and solve on their answer sheet. This activity does include and ANSWER KEY for the teacher. These cards are great for math centers, independent practice, "SCOOT" and other cooperative learning models.