5 Mistakes Teachers Make When Teaching Subitizing

Text says: 5 Mistakes Teachers Make when teaching subitizing. Image shows several subitizing cards with ten frames, dots, tally marks and fingers.

Subitizing. It’s a foundation for number sense and mental math. Students who can subitize have stronger math skills. So, what are some tips and tricks for teaching subitizing? Believe it or not, you can improve your students’ subitizing skills with a few simple routines. Keep reading to learn about common mistakes when teaching subitizing – as well as effective teaching strategies.

But first, let’s start with a critical question:

What does subitizing mean?

Subitizing is the ability to rapidly and automatically recognize a set of objects, without counting. When someone holds up 4 fingers, you don’t have to count them. You just know that there are 4. 

There are two kinds of subitizing: perceptual and conceptual. Perceptual subitizing involves small sets. It precedes conceptual subitizing. Conceptual subitizing involves larger numbers. For instance, when you see 8, you might see 4 and 4.

Subitizing is closely tied to number sense. Subitizing larger numbers helps students develop flexibility with numbers. This flexibility helps them see that numbers are composed 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.

How do students develop subitizing skills?

Students develop subitizing skills by working with number sets – groups of objects, fingers etc. You might use games and quick flashcards to teach subitizing. These activities build automaticity, while keeping the practice fun and engaging for kids.

Photo of several subitizing cards that can be used for a game.


But, there are a few common mistakes teachers make when teaching subitizing. Fixing these mistakes can really strengthen your students’ subitizing skills.

What are the most common mistakes when teaching subitizing?

  • Using “Quick Images” that aren’t quick
  • Using only one kind of image
  • Accidentally encouraging counting
  • Starting with too many numbers
  • Only focusing on the answer

Here are some tips and tricks for teaching subitizing:

Keep “Quick Images” Quick

Quick images are a great way to teach subitizing. These are large flashcards with dot patterns (or other sets of objects.) First, the teacher quickly shows the card. Then the students call out the number of dots on the card. (Learn more about using these subitizing cards in your room here.)

Photo of subitizing cards that can be used as Quick Images in the classroom.

Be careful not to leave the cards up (visible to the students) too long. More than 2-3 seconds gives students time to count the dots. Remember, subitizing is recognizing the quantity without counting. Kids need to recognize these patterns quickly.

Are you new to subitizing cards, but don’t have time to make your own? I have a set of subitizing cards in my store that use ten-frames, dot patterns, dominoes, finger patterns and tally marks. All you have to do is print and they are ready to use! Grab them here!

Use Multiple Types of Images

Ten-frames are really popular. And they definitely help with subitizing. But, the whole point of subitizing is flexibility. If you only use ten-frames, your students will only be quick with ten-frames. But they may not quickly recognize patterns on dice or with fingers.

It’s important to expose students to a variety of images to subitize. You can do this by using little animal stickers (instead of dots) in your ten-frames. It’s also helpful to expose students to other patterns, such as dominoes, tally marks, and finger patterns.

Two images of groups of 5 dots. The first looks like the dots on dice. The second shows 2 dots on top and 3 on the bottom.

Discourage Counting

Sometimes teachers accidentally encourage kids to count the images. You might use the word “count” when you mean “say the number.” For example:

  • Count how many.
  • Can you count to check?

You might also encourage counting is by allowing too much time to respond. Remember, the goal is to recognize the quantity quickly, without counting. This is especially true with larger numbers. Instead of counting, encourage students to use what they already know. Breaking larger groups into smaller sets helps them subitize faster.

For instance, with the second card above, a child might quickly see a group of 2 and a group of 3. They may start with the 3 and count up 2 more, reaching 5. Even with counting on, this is more efficient than counting all.

This is especially important during subitizing games, such as this subitizing war game. When playing with a partner, students are more likely to revert to counting objects, so it’s important to roam the room and coach kids for automaticity when needed.

Photo shows a stack of cards, with two turned over. The two visible cards show 13 tally marks and 5 fingers. This subitizing war game makes teaching subitizing fun for kids.

Emphasize quick recognition of patterns. This leaves brain power for other parts of problem solving. It’s a similar process to reading. When students automatically recognize words, they can attend more to comprehension. Similarly, automatic recognition of patterns allows students to do some “mental gymnastics” to solve math problems. Being automatic from the beginning prepares students for mental math.

Start with just a few numbers

Don’t overwhelm students from the beginning. Instead, work with numbers to 4 or 5 first. This will help students develop perceptual subitizing skills. Once they have developed automaticity with these number sets, work with numbers to 10. 

As you move to larger numbers, start with patterns that make it easy to see combinations. Some examples are below. This will allow students to use what they already know to identify larger number sets. Once you recognize 3, it’s easier to recognize 6 as two sets of 3. Making the patterns easier to see helps encourage students to subitize, rather than count. They may need to start by seeing 3 and counting on. This is appropriate for larger numbers.

Focus on the Process

One final mistake when teaching subitizing is to focus solely on the answer. A quick answer (without explanation) is appropriate for numbers to 5. However, when you move to slightly larger numbers, it is important to have conversations about how students figured out the answer. For instance, when seeing 6 dots, one student might see it as a group of 4 and 2 more. Another child could see it as 3 on top and 3 on the bottom. This builds flexibility with numbers.

Fix those mistakes when teaching subitizing

Help your students develop strong subitizing skills by remembering these tips:

  • Keep “Quick Images” quick
  • Use multiple types of images
  • Discourage counting
  • Start with just a few numbers
  • Focus on the process

By making small changes to your instruction, you will help your students become amazing mathematicians. Their strong subitizing skills will help them mentally solve math problems with ease.

Looking for the products shown in this post? Get them here:

Subitizing Cards

Subitizing War

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Text says: 5 Mistakes Teachers Make when teaching subitizing. Image shows several subitizing cards with ten frames, dots, tally marks and fingers.

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