Practice two-digit subtraction with regrouping using the standard algorithm alongside the disk model in a place value chart. See the connection between the regrouping in the disk model and the steps in the standard algorithm
A. Represent and solve 2-digit subtraction problems without exchanging using a disk model
B. Subtract 2-digit numbers without exchanging using place value cards to subtract tens and ones separately
C. Solve 2-digit column subtraction without exchanging
D. Exchange a ten for ones using a disk model
E. Subtract 2-digit numbers with exchanging using a disk model
F. Subtract 2-digit numbers with exchanging using place value cards
H. Solve 2-digit column subtraction with exchanging (Level 1)
I. Solve 2-digit column subtraction with exchanging (Level 2)
J. Solve 2-digit column subtraction with and without exchanging
K. Solve 2- and 3-digit column subtraction with and without exchanging ones (Level 1)
L. Solve 2- and 3-digit column subtraction with and without exchanging ones (Level 2)