Experiences over time are necessary for young children to build understandings about measurement concepts. In prekindergarten and kindergarten, students begin to develop these understandings when they compare objects and then describe these comparisons. Later, they begin to explore the measurement of length using non-standard units.
 

Students continue to measure objects using a variety of non-standard units in the beginning of Grade 1. These experiences are essential before beginning to measure with standard units. When students measure with different non-standard units, they begin to understand that some of these units are more efficient than others for measuring a specific attribute. This thinking can be transferred to the idea that some standard units are more efficient than others for measuring an attribute of an object.
 

Before students begin measuring with standard units, they need to have an understanding of the measurement process using non-standard units. They must also recognize the need for standard units. It is recommended that students begin using standard units by using single inch units to measure length (e.g., "inch worms"). Then introduce an inch ruler with only inch markings. Later a half-inch ruler can be used.
 

 

Encourage students to estimate the length of an object or picture in inches first. This helps students develop number sense. Support them in using estimating terms such as: about, closer to, almost, just a little smaller, too much, or way too high when they describe estimates. When children are developing understandings of measuring to the nearest inch, provide objects that are close to a whole inch marking (e.g., 4 and 4 ). Estimating skills require repeated experiences in everyday situations.
 

Resources:

Juanita V. Copley. The Young Child and Mathematics. Washington, DC: National Association for the Education of Young Children, 2000.
Marilyn Burns. About Teaching Mathematics A K-8 Resource. Sausalito, CA: Math Solutions Publications, 1992.
National Council of Teachers of Mathematics. Curriculum and Evaluation Standards for School Mathematic. Reston, VA: NCTM, 1992.
Joseph N. Payne (ed). Mathematics for the Young Child. Reston, VA: National Council of Teachers of Mathematics, 1990.