Barbara Soots, Washington OSPI OER Project, Washington OSPI Mathematics Department
Material Type:
Teaching/Learning Strategy
Preschool, Lower Primary, Upper Primary, Middle School, High School
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  • OSPI
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  • Washington Office of Superintendent of Public Instruction
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    Education Standards

    MPIR - Clothesline

    MPIR - Clothesline


    Clothesline is one of many Mathematically Productive Instructional Routines (MPIR). They are short (10ish minutes), daily exercises aimed at building number sense. This is one of six different MPIR covered in the Mathematically Productive Instructional Routines collection from the Washington Office of Public Instruction and the Washington Association of Educational Service Districts.

    Why Clothesline?

    In the Clothesline routine students consider and discuss how to place and space numbers in relation to each other on an open number line. Students strengthen their understanding of number relationships, relative magnitude, precision, and equivalencies through this routine. The dynamic nature of the clothesline allows students to explore, manipulate, and make sense of math concepts without memorizing definitions.


    Mathematical Practices:

    The specific task used may expand the Mathematical Practice possibilities, but in general, this routine will encourage students to use:

    SMP 1: Make sense of problems and persevere in solving them
    SMP 2: Reason abstractly and quantitatively
    SMP 3: Construct viable arguments and critique the reasoning of others
    SMP 6: Attend to precision
    SMP 7: Look for and make use of structure.

    What is Clothesline?

    Using a clothesline and foldable number tents a class number line is created. Values are selected to suit the learning of the students. Students compare and describe relationships among quantities, angles, data points, expressions, or other mathematical values.

    Here are some sample videos of Andrew Stadel using the Clothesline Math routine. Find more information about using this routine on his blog.

    How Do I Implement Clothesline?

    Hang a clothesline across the whiteboard, wall, or anywhere in your classroom! Here is a video by Chris Shore about how to set up the actual clothesline. Use index cards or this template to create a set of mathematical values your students can position, compare and discuss. Give a Card Set to a group of students to go place on the clothesline. The group may add, move, remove or create Benchmarks as needed. While the group is placing values students at their desks are creating their own number line on a lapboard. Once all value cards are placed on the clothesline, ask the class if they agree with the group’s response on the clothesline. Discuss the disagreements and errors.

    Another version is what Chris Shore calls “Place or Correct”. Give one card to one student (or a pair of students), and have them place it on the Clothesline. Then hand the next card to another student(s) and offer them to either place that card on the Clothesline OR move a card already on the Clothesline and give their card to another student in class. This strategy can allow for more students to be involved in the placement of value cards and encourages students to be activly processing and working on their whiteboards.

    While placing a few markers on the clothesline to start can offer scaffolding for students new to the routine, try leaving it open to students and see how the thinking and discussion grows. Try it with whole numbers, fractions, algebraic expressions, angles, or many other concepts students learn across the grades.

    This Process and Resource Guide provides simple steps for planning and implementing clothesline. Clothesline Math from Chris Shore is also a great site dedicated to the routine and includes many premade card sets that you can download and print.

    Mathematically Productive Instructional Routines Menu

    Clothesline is one of many Mathematically Productive Instructional Routines (MPIR). Click on one of the images below to see other examples:

    clothesline    teacher and students          boy thinking
                   Clothesline                              My Favorite kNOw                        Notice and Wonder

    number talk in math class     students discussing math          shapes
               Number Talks                                Ten Minute Talk                          Which One Doesn't Belong

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