## ABSTRACT

This chapter discusses three distinguishing characteristics of early algebra, drawing on examples from our longitudinal investigations of four classrooms in an ethnically diverse school in the Greater Boston area. From the second half of Grade 2 to the end of Grade 4, the authors designed and implemented weekly early algebra activities in the classrooms. The activities related to addition, subtraction, multiplication, division, fractions, ratio, proportion, and negative numbers. The authors compare the same students' reasoning and problem solving at the beginning of Grade 3 and in the middle of Grade 4. They show how mathematics educators can exploit topics and discussions so as to bring out the algebraic character of elementary mathematics. The chapter provides various examples of children's drawings, tables, and verbal comments. They tries to show how children are important as points of departure for the introduction of conventional mathematical representational forms.