This video illustrates the use of manipulatives to help students develop fluency in counting by tens and ones. Manipulatives play an important role in gaining understanding in the base-10 system because manipulatives allow students opportunities to view the collection of 10 ones as both a set of 10 objects and 1 unit. When students practice counting numbers greater than 10 with manipulatives, they learn to recognize that numbers may be decomposed into smaller sets, such as tens and ones. Skill in composition and decomposition (i.e., putting together and taking apart quantities) are critical for students to develop fluency with computation.