Math Talk: Subitizing

To refresh my kiddos on some of the foundational skills we'll need for the addition unit, we've been working with sets of objects and our subitizing skills. 'Sue-Bit-Eye-Zing' is defined by the Illinois Early Learning Standards as "the rapid and accurate judgement of how many items there are without counting," 6.A.ECb. The idea is fluency, specific to a set of objects and quantity rather than of simply the numeral. The Erikson Institute has some great resources at erikson.earlymath.edu.

We continue to work on the skill with dot cards, pictured above. First, they were part of direct instruction during our math talks. Now, I keep a pile by the door in our classroom that travels with us to specials classes for flashcard-style quizzes if we arrive early or have to wait.

Anyway, today we reviewed subitizing with our number of the day, 12. The students were talking to each other about the "right" way to show 12 with dots, so we studied different examples on the SmartBoard. It lead to some hearty conversation, and I hope connections to a big idea!

Here is a screenshot of our discussion. The first two boxes in the top row were mine, drawn last.

The four boxes in the second row were student-drawn, by four different volunteers.

This lesson was worth sharing and seemed powerful to see and talk about the different sets of 12 because we had previously observed the different sets in isolation. Subitizing is usually about fluency. For us, it was about analysis today. 

Most kiddos seemed to understand that ALL the sets above are the "right" way to show what we know about 12. We also agreed that our brains are happiest when we can find more than one way to show a quantity (their words, not mine...happily). 

Have you tried subitizing? Have you tried analyzing sets in this way? Leaves your tips and tricks below!