Elementary, middle, and high school mathematics teachers (N = 105) ranked a
set of mathematics problems based on expectations of their relative proble
m-solving difficulty. Teachers also rated their levels of agreement to a va
riety of reform-based statements on teaching and learning mathematics. Anal
yses suggest that teachers hold a symbol-precedence view of student mathema
tical development, wherein arithmetic reasoning strictly precedes algebraic
reasoning, and symbolic problem-solving develops prior to verbal reasoning
. High school teachers were most likely to hold the symbol-precedence view
and made the poorest predictions of students' performances, whereas middle
school teachers' predictions were most accurate. The discord between teache
rs' reform-based beliefs and their instructional decisions appears to be in
fluenced by textbook organization, which institutionalizes the symbol-prece
dence view. Because of their extensive content training, high school teache
rs may be particularly susceptible to an expert blindspot, whereby they ove
restimate the accessibility of symbol-based representations and procedures
for students' learning introductory algebra.