Column addition is a way of adding numbers together. It's helpful when you're adding two-digit or three-digit numbers together. When you do column addition, you lay out the numbers you are adding ...

Karen C. Fuson, Diana Wearne, James C. Hiebert, Hanlie G. Murray, Pieter G. Human, Alwyn I. Olivier, Thomas P. Carpenter and Elizabeth Fennema Researchers from 4 projects with a problem-solving ...