## Compare, Order, and Measure Length

Measurement is an important area of study because it provides a link between mathematics and our physical environment. At this age, most children have few, if any, measurement skills. Children base their decisions about length by comparing the endpoints of paths and objects. They do not conserve length or distance. Measurement provides opportunities for children to revisit the sorting process by making comparisons and sorting objects into categories such as “longer than my hand” and “shorter than my hand.”

As children focus on length, they also engage in the process of measurement-linking a number with a repeated unit to see how many of the unit is needed to approximate the length of the object. Children measure with nonstandard units such as plastic cubes, their own hands, or paper clips. This lets them focus on counting the number of units needed to fit the length of an object. Children learn language which reflects that measurement may be approximate: A line segment may be about 6 paper clips long, between 7 and 8 blocks long, or just a little more than 1 hand long. After some experience with nonstandard units such as paper clips, children also estimate lengths in these units and then use the units to measure and verify the actual lengths.

Teaching Model: Compare, Order, and Measure Length