Forty first-grade teachers' pedagogical content knowledge of children's solutions of addition and subtraction word problems was investigated. Most teachers could identify many of the critical distinctions between problems, and the primary strategies used to solve them, but did not have a coherent organizational scheme. (MNS)

After a year of instruction, 70 kindergarten children were individually interviewed as they solved basic, multistep, and nonroutine word problems. Thirty-two used a valid strategy for all 9 problems, and 44 correctly answered 7 or more problems. Modeling provided a unifying framework for thinking about problem solving. (Author/MDH)