Several years ago, while I was teaching Kindergarten, I was introduced to the concept of subitizing. If you’re not familiar with it, subitizing is getting students to recognize quantities in a group without counting them. My class was working on identifying quantities in a ten frame, and they loved practicing with subitizing cards. I printed various ten frames on brightly colored cardstock, turned it into a game, and instantly had student engagement! Since I’ve moved up to 3rd grade, I have learned so many more ways to use subitizing to help students develop procedural and conceptual number skills.
In early grades, we want students to recognize groups of objects. With Kindergarten and 1st grade, I worked on single ten frames, 1 face of a die, and 1 group of tally marks.
For subitizing practice, you can print pictures like these (on cardstock and laminate for future use) and gather students on the carpet or at the small group table. Show the students one card at a time for only a few seconds, then turn it over and ask them if they can tell you how many dots/tally marks they saw in the picture. Three seconds is a good amount of time for the single sets- if you see students start counting on their fingers turn the card over. The purpose is to get students recognizing numbers of objects without counting. I tell students to “take a picture” with their brain so that they can still see the image when I turn the card over. There is also a great **FREE** iPad app called Number Flash that you can practice with!
With the older grades, I use subitizing cards for addition practice. With this strategy, you can show them a card with 2 or more groups of items. You should still encourage students to take a photo with their mind, but the goal is that they recognize one group of 10 and one group of 4, and they can quickly add the groups together. I give around 5-6 seconds for these cards. Again, flip them over if you catch students counting. Below are some examples of groups I put on my conceptual subitizing cards.
Developing early numeracy understanding and addition fluency is so important, and subitizing is a great way to practice those skills! Your students will love the challenge of recognizing/adding numbers in only a few seconds, and you will love the increase in basic number sense that subitizing gives your students!