ABSTRACT
There are now several preschool mathematics programs for which reliable evidence of effectiveness has been reported (e.g., Clements & Sarama, 2008; Gormley, Phillips, & Gayer, 2008; Klein, Starkey, Clements, Sarama, & Iyer, 2008). These programs represent the state of the art in early childhood mathematics, incorporating the best knowledge available today as to what young children need to learn about mathematics and how they can be supported in learning it. That knowledge, however, is still incomplete. Ongoing research in early childhood education (e.g., Anthony & Walshaw, 2009; Mulligan & Mitchelmore, 2009) and in developmental psychology (cf., Geary, 2006; Mix, 2010; Sophian, 2007) has the potential to further advance our knowledge about how young children think and learn about mathematics, and about how instruction can contribute to that thinking and learning.
