Add together two decimal numbers (to the thousands place). Rewrite the addition problem in column form and use disk models to assist in finding the sum with any necessary regrouping
A. Add numbers to the hundredths place with regrouping using a disk model
B. Add numbers to the thousandths place with regrouping using a disk model
D. Add numbers to the thousandths place with regrouping using column addition
E. Subtract numbers to the hundredths place with regrouping using a disk model
F. Subtract numbers to the thousandths place with regrouping using a disk model
G. Subtract numbers to the thousandths place with regrouping using column subtraction and a disk model
H. Subtract numbers of different lengths to the thousandths place with regrouping using column subtraction and a disk model
I. Subtract numbers to the thousandths place with regrouping using column subtraction