# Subitizing: What Is It? Why Teach It?

Author: Douglas H. Clements

Journal: Teaching Children Mathematics
Publication Date: March 1999

Clementsâ€™ (1999) article on subitizing provides a brief history of research on subitizing and clearly describes the two types of subitizing: perceptual (instantly seeing small quantities) and conceptual (involving larger quantities that may appear in familiar arrangements or perhaps adding on or composing two smaller quantities together). The article provides a number of implications for teaching along with several examples for addressing subitizing in early childhood classrooms.