MAFS.2.MD.2.5 Use addition and subtraction within 100 to solve word problems involving lengths that are given in the same units, e.g., by using drawings (such as drawings of rulers) and equations with a symbol for the unknown number to represent the problem.

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

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

  • Use concrete tools or pictures to make sense of a word problem and solve it
  • Write an equation with a symbol for the unknown to represent the problem
  • Explain how they solved the problems

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

  • Provide lots of opportunities for students to make sense of word problems involving length
  • Provide opportunities for students to see different ways that classmates solve problems—using tools and pictures to model
  • Provide opportunities for students to connect the models and pictures to the equations that are used
  • Connect this type of problem solving to 2.NBT.2.7

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

  • Ask:  Jaesir jumped 38 inches.  Leilani jumped 29 inches.  How many inches further did Jaesir jump that Leilani?  Write an equation with an unknown to solve the problem.
    • Sample answer that would indicate understanding:  The student may use tools or a picture to represent the two jumps and determine that Jaesir jumped 9 inches further.29 + ? = 38  OR  38 – 29 = ?
    • Sample answer that indicates an incomplete understanding or a misconception:    The student may use tools or a picture to model the story, but say that Jaesir jumped 61 inches further then Leilani.38 + 29 = ?
  • Ask: Students are using some string to divide the classroom into two areas.  They have a piece that is 26 inches, a piece that is 17 inches, and a piece that is 34 inches.  How much string do they have?  Write an equation with an unknown to solve the problem.
    • Sample answer that would indicate understanding:  The student may use tools or a picture to represent the pieces of string, and say they had 77 inches of string.26 + 17 + 34 = ?
    • Sample answer that indicates an incomplete understanding or a misconception:    The student may use tools or a picture to model the pieces of string, but not give the correct total.  They may only add two numbers.26 + 17 = ? OR 17 + 34 = ?

[divider] [/divider] Additional Resources:

Additional in depth content knowledge

Video:

https://learnzillion.com/lesson_plans/4629-solve-length-word-problems-using-a-number-line/

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

  1. The teacher should give the student the String For Bracelets worksheet and read the problem aloud to the student.Virginia has 34 centimeters of string to make a bracelet and her friend, Arianna, has 42 centimeters of string. How much more string, in centimeters, does Arianna have than Virginia?
  2. The teacher then asks the student to write an equation to represent the problem.Note: Both 42 – 34 = ? and 34 + ? = 42 are acceptable variations of equations that represent the problem.
  3. The teacher then asks the student, “How much more string, in centimeters, does Arianna have than Virginia?” Once the student provides an answer (e.g., eight), the teacher should ask, “Eight what?”

MFAS_StringForBracelets_Worksheet.docx

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