2.MD.A.4

Measure to determine how much longer one object is than another, expressing the length difference in terms of a standard length unit.

Summary:

The study of measurement allows for opportunities to integrate a variety of mathematical processes for use in problem-solving. This standard focuses on students’ ability to accurately measure and compare two objects of varying length using standard length units. Students can use a variety of ways to determine the difference in length between two objects; some students may choose a subtraction equation, count on strategies, or comparative drawings/graphic representations. This exploration is another example of math’s value in the real-world context.

Understanding the Standard:

• Students should have multiple opportunities to master the measurement of a variety of objects using a standard unit.
• The use of manipulatives and other technologies should be used.
• Using standard units, have students measure two similar objects but with obvious differences in lengths. Once the students have measured both objects, they should be guided to solve for the differences in their lengths by using appropriate strategies.

Questions to Focus Instruction:

• Can students choose the appropriate standard measuring tool?
• Can students accurately measure the length of two objects in standard units?
• Can students state the difference in units of length, i.e., "The pencil is 2 inches longer than the crayon."?
• Can students determine the difference in length between two objects and use an appropriate strategy to express that difference?
• Can students state the difference in units of length, for example, "the pencil is 2 inches longer than the crayon."?

Skills

Prior to: Students can sort, order, and classify comparable objects according to length, a specific measurable attribute. Students can use the appropriate measuring tool to determine the exact whole number measurement of an object in custom and metric units of measure.