Data are reported from the first and second individual interviews conducted in 1980 in the second phase of a 3-year study on addition and subtraction using verbal problem solving. The second phase is concerned with children's performance on verbal addition and subtraction problems which contain two-digit numbers, half of which require regrouping for correct computational solutions. Ninety-six second-grade children in two schools in Wisconsin that used the Developing Mathematical Processes program were individually administered 12 verbal problems that could be solved using addition or subtraction. Responses were coded in terms of appropriateness of strategy, correct or incorrect answer, type of error, mode of representation, and solution strategy. Group data on the problems as well as information on individual subjects are reported. Appendices contain sample problem tasks and individual student profiles. (Author/MNS)