Need to Knows in a K-2 Class

The “Need to Know” videos were created in partnership with Avondale Elementary School District.


Subitizing and Comparison





Rote Counting, One-to-One Correspondence, & Cardinality





Hierarchical Inclusion, Number Conservation, & Unitizing





Extending the Number Sense Trajectory to Build Place Value Understanding




Misconceptions in Geometry





Progression of a Number Line





Properties of Addition




Fractions in the Early Grades





Base Ten Models for Operations (Addition and Subtraction)





Regrouping with Subtraction