The definition of subitizing is the ability to instantly recognize “how many” in a set of objects without counting them. For example, when someone holds up 3 fingers, you don’t have to count them. You just know that there are 3. The ability to subitize is an essential part of developing number sense skills. Students who can subitize are more successful and enjoy math more.
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I remember the first time I heard about subitizing, and I was surprised that it was something I did but didn’t know it had a name. It is not a term anyone (but maybe a teacher) talks about! The name makes it sound like a difficult skill, but you’ll be surprised at how easy it is to teach this math concept to children. It makes a perfect warm-up to my lessons with little effort and significant results.
Definition of subitzing
The definition of subitizing is the ability to instantly recognize “how many” in a small set.
What Does Subitize Mean?
A perfect example of subitizing is dice; when you roll a die and see two dots on top, you instantly recognize it as representing a quantity of two. You don’t need to count each dot on the dice to figure it out.
Subitizing is the ability to rapidly and automatically recognize a set of objects without counting.
Two Types of Subitizing
There are two types of subitizing: perceptual and conceptual. The definition of subitizing are:
- Perceptual subitizing involves small sets. It precedes conceptual subitizing.
- Conceptual subitizing involves larger numbers. It is recognizing smaller groups within a larger set and adding those small groups together. For instance, when you see 8, you might see 4 and 4.
Why is Subitizing Important?
Subitizing is an important part of developing basic number sense skills. Subitizing larger numbers helps students develop flexibility with numbers. This flexibility enables them to see that numbers are composed in different ways. For instance, 10 can be 4 and 6 or 3 and 7. This flexibility helps them become more efficient with mental math. Teaching subitizing sets students up for future success in math.
When you teach young children how to subitize, you also teach them to recognize patterns. This, in turn, builds their number sense.
Subitize Meaning by Grade Level
Subitizing strengthens a child’s understanding of what numbers mean and how they relate to one another. When children are taught to subitize, their attention is drawn to the groups and patterns they see, and it becomes a visual representation of addition and subtraction.
How to Teach Subitizing to Preschoolers?
It is essential to start with perceptual subitizing. You ask them to recognize smaller sets first before moving on to the larger sets like 6 and up.
Once students are proficient with subitizing a set of objects to 5, you can move to conceptual subitizing. Conceptual subitizing is a more advanced skill using a larger number of objects.
How to Teach Subitizing in Kindergarten?
Once students are proficient with subitizing a set of objects to 5, you can move to sets to 10 and then to 20.
It’s important to expose students to a variety of images to subitize. You can do this by using various images (dots or different images). It’s also helpful to expose students to other patterns, such as dominoes or dice.
When strengthening a child’s subitizing skills, we are teaching the following Core standards:
CCSS.MATH.CONTENT.K.OA.A.1 Represent addition and subtraction with objects, fingers, mental images, drawings, sounds (e.g., claps), acting out situations, verbal explanations, expressions, or equations.
CCSS.MATH.CONTENT.K.OA.A.2 Solve addition and subtraction word problems, and add and subtract within 10, e.g., by using objects or drawings to represent the problem.
CCSS.MATH.CONTENT.K.OA.A.3 Decompose numbers less than or equal to 10 into pairs in more than one way, e.g., by using objects or drawings, and record each decomposition by a drawing or equation (e.g., 5 = 2 + 3 and 5 = 4 + 1).
CCSS.MATH.CONTENT.K.OA.A.4 For any number from 1 to 9, find the number that makes 10 when added to the given number, e.g., by using objects or drawings, and record the answer with a drawing or equation.
CCSS.MATH.CONTENT.K.OA.A.5 Fluently add and subtract within 5.
How to Teach Subitizing?
The simplest way is to show students a collection of objects for a few seconds, and then the children take a mental image of the set.
Remember to quickly show the image, so students are not counting. The age of the students and their experience in subitizing will determine how fast to flash the image. You might need to give them more time initially or with younger children.
It is not just about how many images. A quick answer is appropriate for numbers to 5. However, it is important to have conversations about how students figured out the solution when moving to slightly larger numbers. Breaking larger groups into smaller sets helps them subitize faster. For example, when seeing 7 dots, one student might see it as a group of 5 and 2 more. Another child could see it a different way. This builds flexibility with numbers and is the foundation for addition and subtraction.
Subitizing with Ten Frames
It’s important to expose students to a variety of images to subitize. For example, show students dots or pictures in a five frame or ten frames and ask, “What do you see?” “How do you see it?”
Remember to start with sets to 5, then progress to 10.
- Ten Frames Free Printable (plus Five and Double Ten Frames)
- Free Button Subitizing Images
- Subitizing to 5 or Subitizing to 10 Winter Google Slides
Read more about using ten frames at… Why Using Ten Frames for Math to Develop Understanding is Effective?
Subitizing with Images
Show students arrangements of dots of images not in five or ten frames. Students need to subitize a variety of images in different ways.
Subitizing with Games
Playing games using dominoes, dice, or cards is a fun way to have students practice subitizing. You can also just flash images of dominos, dice, or cards to have students subitize.
- Free Subitizing Images with Dominoes and Dice
- Free Math Puzzles
- Build It!- Give students counters and have them show you an arrangement with a certain number of counters. Then, have them show you another way to show that same number of counters. Ask, “How many do you see?” Each day focuses on a different number of counters.
- More and Less- Show students a set of counters. Ask, “What number is one more? How do you know?”
Subitizing with Part- Part- Whole- Mat Activities
Students are shown some images to subitize. Then, they have to determine how many are covered. These are great for building fluency with addition and subtraction.
- Part- Part- Whole Mat Activities Bundle
- Free Math Puzzles with Part- Part- Whole Activities included
Read more about using the Part-Part-Whole Strategy here…How to Use the Powerful Part-Part-Whole Strategy to Improve Number Sense.
Composing and Decomposing Numbers
Subitizing is about composing (putting together) and decomposing (breaking apart) numbers. These Free Composing and Decomposing Number Anchor Charts are great visuals for students.
In addition, you can use these resources to practice decomposing and composing with students.
- Decompose and Compose Numbers
- Composing Decomposing Numbers (Slides and Worksheets)
Read more at… Discover Fun and Exciting Activities and Upack What is Decomposing in Math?
Subitizing for Preschool & Subitize Kindergarten with Number Talks
A Number Talk is a short, ongoing daily routine that provides students with meaningful practice with computation. A Number Talk is a powerful tool for helping students develop computational fluency. The expectation is that they will use number relationships and the structures of numbers to add, subtract, multiply, and divide.
Number Talks should be structured as short sessions (5-15 minutes) and are most effective when done every day. Read more about Number Talks.
- ntimages.weebly.com/ntimages.weebly.com – Curated by Pierre Tranche. This website has a collection of images, including dots, number strings, and arrays that can be used for subtitizing.
Subitizing Activities Online
Ideas for Subitizing Math Games
- Free Subitizing Dot Cards for Kindergarten
- Free Subitizing Google Slides
- Subitizing Video
- Subitize to 10 Jack Harmann
Additional Information & Resources
- More & Less Activities
- Part- Part- Whole Activities Bundle
- Counting to 20 Freebie
- Show the Number
- Top 3 Easy and Successful Alternatives to a Counting Worksheet
- How to use Engaging Math Puzzles for Fun to Build Number Sense
Subitizing and Counting
The definition of subitizing is all about recognizing “how many” in a set of objects without counting them. Providing students different opportunities to subitize can be fun and is important in building number sense. Start with sets to 5, then progress to larger numbers. In addition, this supports students’ understanding of composing and decomposing numbers and addition and subtraction fluency.
Get this Freebie of 71 Math Number Puzzles delivered to your inbox to use with your students. Providing opportunities to do math puzzles daily is one way to help students develop their number sense and make math fun. You can also sign up to receive other freebies from me Here at Easternshoremathteacher.com.
Try out some of these resources and see how much your students enjoy subitizing. Let me know your favorite definition of subitizing and activities that support it?
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