• 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.


    In this video Andrew Stadel describes the basics of Clothesline Math. Find more information and resources on his website.

     Image of clothespins on clothesline


    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.