MAFS.2.MD.1.4 Measure to determine how much longer one object is than another, expressing the length difference in terms of a standard length unit.

Cognitive Complexity Level: 2 – Basic Application of Skills and Concepts

[divider] [/divider] Students are able to… 

  • Choose two objects, measure them, and then compare the lengths
  • Explain the length difference between two objects using precise language

[divider] [/divider] Students are able to…because teachers:

  • Provide time for students to practice finding two objects, measuring them, and finding the difference in length
  • Remind students to make direct comparisons between objects. This can be done by laying the objects next to each other.  For example, the pencil is 3 inches longer than the crayon.

 [divider] [/divider] Questions to ask students:

  • Ask:  How do you know that object is ____inches/cm longer than the _______? 
    • Sample answer that would indicate understanding:  I know this object is ____longer than the ____, because I lined them up and measured the difference.  OR I know this object is ____longer than the ____, because I measured them both and then subtracted the two measurements. 
    • Sample answer that indicates an incomplete understanding or a misconception:  The pencil is longer than the crayon; however, the student is not able to explain how much longer.
    • Sample answer that indicates an incomplete understanding or a misconception: The pencil is 8 inches longer than the crayon.  The student places the objects next to each other but does not line them up when finding the difference in measurement.

[divider] [/divider] Additional Resources:

Additional in depth content knowledge

Video:

https://learnzillion.com/lesson_plans/6984-find-the-difference-in-the-length-of-two-objects-using-addition/

[divider] [/divider] Sample Formative Assessment Tasks:

This task should be completed individually with students to allow the teacher to observe if and how students are measuring length.

  1. The teacher provides the student with the attached Dragonflies and Grasshoppers worksheet and a centimeter ruler.
  2. Then, the teacher asks the student to measure both insects to determine which insect is longer and how much longer it is than the other insect. The teacher should observe if the student uses a ruler to measure the two images and describes the difference in their lengths in terms of centimeters.
  3. After the student provides an answer, the teacher should prompt the student to explain his or her thinking.

MFAS_DragonfliesAndGrasshoppers_Worksheet.docx

Note: This task requires the student to measure the lengths of items shown on a worksheet. The attached worksheet has been saved as a PDF to ensure that the lengths result in whole number measures, as intended. However, many printers distort lengths in the process of printing. We encourage the teacher to try this task first before giving it to students to ensure that each item can be measured using whole numbers of units

[divider] [/divider] Resources/Tasks to Support Your Child at Home:

  • Have your child choose objects from home to measure the length of using a ruler.  Have them describe how the lengths compare using the language: shorter and longer.  Have them record the lengths and find the difference in length of the two objects by subtracting.
  • Khan Academy Tutorial Video: Length Word Problems 
  • Khan Academy Practice: Length Word Problems