What is unitizing in math?

Answer 1

Unitizing is understanding that numbers can be arranged in groups and that these groups can then in turn be counted as individual units. Thus, for example, five fingers can be grouped together to make a hand. Then hands can be counted such that three hands can be counted to be the equivalent of fifteen fingers.

Another example is that eggs can be counted in packets containing 12 or a dozen, such that if you buy two dozen you are getting twenty four eggs or twenty four eggs is the same as two units of a dozen.

When the groups contain ten items we can use them as the basis of the ten-based counting system which provides the foundation for place value.