Enter the missing addend for a sum of 20. A pair of related equations make up each problem. Cube models are provided if assistance is needed
A. Identify a missing single-digit addend to reach the next round number with and without a model of base-10 blocks
C. Solve +/- equations that do not cross a ten based on a number line model
D. Solve +/- equations within 100
E. Model and solve +/- equations across 10 using base-10 blocks
F. Solve +/- equations across 10 (Part 1)
G. Solve +/- equations across 10 (Part 2)
H. Solve +/- equations within 100