Counting & Cardinality is the ability to understand the relationship between numbers and quantities. Before learning to count, a student needs to understand “one to one correspondence.” This means they are able to match one object to one other object. They also need to understand that the total quantity in a set can be determined by subitizing or counting. While subitizing allows students to perceive the cardinality of small sets, counting requires them to understand that the last number in the counting sequence represents the quantity of the set.

Students may have difficulty in the following areas:

• Consistently using the number words in the same order.
• Counting every item in a set only once and using only one number word.
• Understanding that the last number word used represents the cardinality of the set.
• Recognizing that any collection of like or unlike items can be counted as a set.
• Understanding that the result is the same no matter the order in which the objects are
counted.