Subitizing is "instantly seeing how many." Subitizing is a relatively new concept for me. Children
often have little experience with subitizing. When I first learned about
this concept, I thought it pertained only to kindergarten, first grade,
and struggling students beyond those years. However, I have now seen
that children of all ages benefit from subitizing.
What is subitizing, and why is it important? Clements and Sarama (2009) define two types of subitizing. The first,
perceptual subitizing,
pertains to the ability to both perceive intuitively and simultaneously
the amount in small number sets. No counting is necessary, you just
know the amount when you see it. Children develop the prerequisite
skills for perceptual subitization at a young age. According to Clements
and Sarama, children begin naming collections of 1, 2, and 3 from ages
1-2. By age three, children can also create collections made of 1-3
objects, sometimes 4. Perceptual subitization up to a collection of 4
occurs at age four, and the recognition of sets of 5 develops at age
five.
The second type,
conceptual subitizing, relates to the ability
to instantly see the parts, and join them together to make a whole. For
example, given a picture of five arranged with three and two dots, a
conceptual subitizer would see 3 and 2, and know that makes 5. Again, no
mathematical operations may be consciously enacted, but rather, an
instant recognition that the parts make that whole. As children
progress, subitizing helps with the visualization of operations and
mental math. Conceptual subitizing to five and ten begins at age five.
By age six, children are able to conceptually subitize to 20. At this
age, five and ten-frames are helpful organizers for promoting subitizing
at these higher levels. Skip and counting and place value with
subitization begin at age seven, and by age eight, children see
multiplicative relationships, such as 5 groups of 10, and 4 groups of 3,
which makes 50 and 12, so 62 dots. As you can see, children benefit
from subitizing activities well into third grade and beyond.
In my search for spectacular subitization activities for my Tier II students, I have come across a few really great ones. Just click the pictures to download these freebies!
Happy subitizing!!!
