Quick . . . how many dots are on the dice in the picture above? If you said 11 without counting each of the dots, you were subitizing (pronounced soo-bi-tize). Subitizing is instantly recognizing quantities in random, organized, and structured arrangements. It is a very important foundational math skill because it allows students to move away from counting by ones to seeing numbers as chunks. It is a precursor to "counting on" and eventually addition, subtraction, and multiplication.
The pips (or dots) on dice are an example of a structured arrangement. We instantly recognize the way numbers look as the dots are arranged on a die. 11 is seen as 6, and 5 more. It is much quicker than counting all of the pips. It also leads to the understanding of 6+5=11.
By learning to subitize, students progress through steps, such as:
- "I counted all the dots."
- "I said 6 . . . 7,8,9,10,11."
- "I know 6 and 6 is 12, so it is 1 less" or "I know 5 and 5 is 10 and it is 1 more."
- "I know 6 and 5 is 11."
Other examples of subitizing activities are using fingers (not having to count all 5 fingers on one hand), ten frames, tally marks and arranged objects. The good news is strong subitizing skills can be developed with practice. Children benefit from explaining how they were able to identify a quantity.
Here is a link to subitizing activites and games you can do with your child.
http://teachmath.openschoolnetwork.ca/grade-1/number-sense/subitizing/
