Solve for three missing terms in a set of three equations. Each equation has one or two symbols in place of a term. Find the missing numbers
A. Solve missing addend equations
B. Solve multi-step missing addend equations
C. Solve for missing addends in paired equations (Level 1)
E. Solve for missing addends in paired equations (Level 2)
F. Solve missing addend equations containing a 0
G. Solve for missing addends in paired equations containing a 0