In mathematics education research, there are two traditional references
for describing mathematical thinking: one is focused on the
mathematical process and the other on conceptual development.
The well-known references of the first type are the articles of Polya
[1945, 1957, 1962, 1965]. He analyzed his own experience as a mathematician.
His book was written for people challenged by the task given
by him. To adopt his ideas in the classroom, teachers have to change
the examples to make them understandable and challenging for their
children. Mason [1982] refocused on the process from the educational
viewpoints. Stacey [2007] described the importance of mathematical
thinking and selected twin pairs of activities - "specializing and generalizing"
and "conjecturing and convincing" - as follows: