Learn how to exchange 1 hundred disk for 10 tens disks, and then 1 of those tens disks for t0 ones disks for a two-step regrouping. This skill is used when there aren't enough ones to subtract, and the tens digit is zero
A. Solve 3-digit column subtraction with exchanging with and without using a disk model
B. Solve 3-digit column subtraction with multiple exchanges
D. Solve 3-digit column subtraction with 2-step exchanges with and without using a disk model
E. Solve 3-digit column subtraction with 2-step exchanges