Choose from a selection of two answers for each numerical expression they are given. Each numerical expression sums to one of the two answers
A. Identify a missing addend in equations with a sum and their turnaround facts
B. Record a model of base-10 blocks as an addition equation
C. Identify the missing addend in equations paired as turnaround facts with sums of 4, 5, 6 and 7
D. Solve for a missing addend in an equation
E. Identify the missing addend in equations paired as turnaround facts with sums of 6, 7, 8 and 9
G. Identify the missing addend in equations paired as turnaround facts with sums of 9 and 10