Add four digit numbers by setting up the problem as column addition and then using disks in a place value chart to visualize the addition. Problems require regrouping in one or two places
A. Add two 4-digit numbers with and without regrouping in one place using a disk model
B. Add two 4-digit numbers with and without regrouping in two places using column addition and a disk model
D. Add multi-digit numbers with regrouping in multiple places using column addition and disk models
E. Add multi-digit numbers with regrouping in multiple places using column addition
F. Add multi-digit numbers using the standard algorithm