Students solve addition problems involving tens numbers by adding the tens digits without a model
A. Add tens numbers (Level 1)
C. Subtract tens numbers (Level 1)
D. Subtract tens numbers (Level 2)
E. Solve addition problems with 2-digit numbers and tens numbers (Level 1)
F. Solve addition problems with 2-digit numbers and tens numbers (Level 2)
G. Solve addition problems with two 2-digit numbers (Level 1)
H. Solve addition problems with two 2-digit numbers (Level 2)
I. Solve addition problems with two 2-digit numbers (Level 3)
J. Solve addition problems with two 2-digit numbers, including regrouping