Can You Do This for Five Minutes Every Day?

By on Aug 8, 2015 in Blog, Blogs about Subitizing and Unitizing | 0 comments

Do you have five minutes every day to do an activity to help your students achieve the critical developmental milestone of unitizing?

Unitizing can be described in a variety of ways. Many definitions of unitizing in math refer to the place value understanding that ten ones can also be thought of as a unit of ten. Unitizing is also described as the understanding that numbers can be organized into groups and these groups can be counted as units.

Our goal as teachers is to provide math experiences in which students understand numbers and their relationships in order to solve problems using non count-by-one strategies.

A quick way you can help your students in their development of unitizing is by exposing them to conceptual subitizing. Show/flash quantities of objects for only a few seconds and ask students to tell the quantity and explain how they know. Quick flashes encourage students to see the objects in groups and move away from count-by-one strategies.

I leave higher quantities of objects up longer for students to see smaller groups of objects within the larger group. When students explain their strategies, I may have the image visible. This way, students can point out the groups they saw. I may even draw a frame around the groups the students saw.

The verbal explanation a student gives is as important or more important as the answer to the question: “How many do or did you see?”

By asking: “How do you know?” or “How did you see that?” teachers can gain valuable information about students’ math thinking. Our goal is to provide opportunities for students to see groups of objects as units and explain their thinking using non count-by-one strategies.

For a sequence of concepts to follow when choosing quantities, click here to see my Math Path for Structuring Numbers. The playing cards in the Teacher Toolkit and the Multiplication Decks are perfect for this activity. I also have a set of 84 subitizing cards on Teachers Pay Teachers.