Numerosity is the ability to count a set of objects using the correct number names in the proper order. Fuson and Hall (1983) assert that the use of cardinal words is one measure of the development of number knowledge. Using words in a cardinal context indicates that children are beginning to understand the manyiness of objects. The use of cardinal words is one of the best indicators that a child is beginning to understand counting and the underlying principles involved.
Numerosity is a concept which children often, but not always, demonstrate with overt behaviors. Understanding cardinality and numerical order, develops with an understanding of numerosity Assessing numerosity skills is one of the most reliable gauges of overall mathematical development in the preschool child
