Comparing Number

Composition Estimator

Sub Trajectory: Numerosity Estimation

Decomposes or partitions to-be-estimated set into convenient subset sizes then recomposes the numerosity. Initially, this is done with regular arrangements using repeated addition or multiplication. Later, the process can be done with irregular arrangements and children more consistently use multiplication skills to recompose.

Activities

You may see this:

Other Examples:

When shown 87 objects spread out and asked for an estimate, the child points to a section and says, "That's about 20 - so 20, 40, 60, 80, Eighty!" The use of repeated addition supports estimation after a visual separation of the objects into 4 parts.
The use of repeated addition supports estimation after a visual separation of the objects into 4 parts.

Help your student become a(n) Composition Estimator

Activities ask children to make reasonable estimation of the number of objects in a set, helping them form benchmarks (what would 10 of these look like? 100?) to guide their estimates using repeated addition and/or multiplication (picture 10 in the bottom of the jar--keep counting by tens up the jar). Scaffolding also includes using regular arrangements of objects and then includes more random arrangements to extend children's competencies.

Estimate How Many [Composition]

Small Group

Estimating Game [Composition Estimator]

Hands-on Math Center