What is Subitizing?
Subitizing is the ability to look at a group of items and quickly and correctly judge how many of them there are. Usually, this means that subitizing occurs with a small number of items. Patterns enhance a person’s ability to subitize. For example most people are able to instantly recognize a grouping of one to six dots on dice.
Subitizing differs from estimating in that successful subitizing occurs rapidly without any sort of number judgement or strategy.
Subitizing is an important executive functioning skill for young children to develop and enhance as it is considered the foundation for basic number sense. It supports future operational fluency and the ability to see relationships and patterns between numbers.
When teaching subitizing, the following vocabulary will be beneficial to ensure learners are able to grasp the basic concept:
Ask students to be on the lookout for places where people ask them to estimate. Some hints to get them started might be:
- Why can we tell what number is on the die without even counting each dot?
- How does the pattern help us make a quick, accurate guess?
- Why do we break up certain numbers the way we do? (i.e. phone numbers, social security numbers, license plates, etc.)
Two Forms of Subitizing
Subitizing occurs in two forms: perceptual and conceptual, which is another reason why this executive functioning skill can be challenging for young learners.
- Commonly found in small children – able to instantly recognize one to three objects
- Built by observation – being shown patterns of three, four, five or more items
- The ability to pair and/or see sets of numbers within larger sets, for example seeing two fours in the eight of a domino
Here are some great ways to encourage your students to have fun with subitizing:
- Break students into groups and have them compete based on which group can remember numbers better – give one group numbers broken into subitized patterns (i.e. phone numbers, larger numbers with commas, etc.) and give the other group the same numbers but with no grouping. Discuss why one group had an easier time remembering the numbers.
- Play with toys that encourage grouping and patterns, like abacuses, dice, and playing cards
- Stock your library with early childhood counting picture books
- Make pattern cards with different patterns of dots and play “around the world” or other games with them