Initial measuring experiences involve direct comparison of two objects to determine which is longer, shorter, or if the objects are the same length. Sorting objects by length presents opportunities for children to see length as a measurable attribute. Encourage students to discuss these comparisons, which help to develop the mathematics vocabulary needed for later work with measurement.

After students have had multiple opportunities to directly compare objects, they are ready to measure objects (and later pictures) with non-standard units. Important ideas about this level of understanding are:

• Units can include body parts (e.g., hands or thumbs) or common classroom items, such as paper clips or snap cubes.
• The use of a variety of non-standard units helps students see that some units are more efficient than others to measure a specific attribute of an object.
• Students measure by placing units alongside or on top of the object and then count the units (quantifying length).
• It is necessary to use a common starting point when comparing and ordering objects by length, or measuring objects or pictures.
• Measurements are never exact therefore, support students in using language such as "closer to", "almost", "about" when they describe the length of an object (e.g., "The book is about 5 cubes long."). This strengthens students' number sense abilities.
• Students should estimate a length before measuring objects and then check their estimate by using units to measure.

Resources:
Joseph N. Payne (ed). Mathematics for the Young Child. Reston, VA: National Council of Teachers of Mathematics, 1990.

National Council of Teachers of Mathematics. Curriculum and Evaluation Standards for School Mathematics, Reston. VA: NCTM, 1992.

Juanita V. Copley. The Young Child and Mathematics. Washington, DC: National Association for the Education of Young Children, 2000.