ABSTRACT
During an autumn morning in our third-grade classroom, four students and the author were problem solving at the circular table in the back of the classroom while the rest of the students worked in their math stations. Brandon was using number sense to solve the problem, although his strategy was not yet efficient. By drawing base ten blocks, he was able to visualize the problem and the amounts. Students who struggle in math often lack number sense. It is difficult to compute without number sense. It is a struggle to find relationships among numbers or equations without number sense. It is more arduous to figure out measurement, geometry, and data problems without number sense. In other words, number sense is the foundational building block for all strands of mathematics. Douglas Clements explains young learners’ number sense development in terms of a learning trajectory. C.
