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Learning Resource Type

Learning Activity

Decomposing Numbers: Part 1

Subject Area





In this activity, students will practice decomposing a number in multiple ways using pictures and recording the decomposition using pictures and numbers.

This activity results from the ALEX Resource Development Summit.

    Mathematics (2019) Grade(s): KG


    Decompose numbers less than or equal to 10 into pairs of smaller numbers in more than one way, by using concrete objects or drawings, and record each decomposition by a drawing or equation.

    Unpacked Content



    • Decompose
    • Equation


    Students know:
    • "equal to" and the concept of equality meaning "the same as."
    • Addition is putting together numbers and subtraction is taking apart numbers.


    Students are able to:
    • Represent quantities physically, pictorially, and symbolically.


    Students understand that:
    • quantities may be named in a variety of ways.


    Learning Objectives

    Learning Objectives

    Students will understand various ways a number can be decomposed and be able to record the decomposition using pictures and numbers.

    Activity Details

    1. The teacher will play the "Grandma's Sweater" video, pausing to discuss how many buttons of each color Grandma has on her sweater.

    2. After the video, the teacher will have students turn and discuss with a partner different ways to decompose 5 that were seen in the video.

    3. The teacher will then ask, "What are some different ways Grandma made 5 using the buttons on her sweater?" (0 and 5, 4 and 1, etc). Transcribe student answers on chart paper or have students transcribe their answers on chart paper. Guide students in adding a numeral to each part within the set as well as the numeral for the entire set (example: for 1 pink button and 4 green buttons, circle the 1 pink button and write 1 underneath, circle the set of 4 green buttons and write 4 underneath, then ask "How many is 1 and 4?" and write 5 under the complete set).

    4. Ask students "Can you think of any other number combinations that make 5 to add to the chart?"

    5. Have students draw a picture of themselves with 5 buttons on their shirt. Have them choose one of the number combinations discussed or one of their own combinations that were not discussed to illustrate one way to decompose 5. Ask students "How did you demonstrate decomposing the number 5?" Have students label the parts of their set as well as the complete set using numerals. To extend this portion, students can draw friends in their picture, illustrating each person with a different way to decompose 5.

    Assessment Strategies

    Assessment Strategies

    1. As turn and talk discussion occurs (step 2), the teacher will listen and assess student knowledge of decomposing 5 specifically listening for students to discuss more than one way 5 was decomposed. 

    2. As whole group discussion occurs (step 3) to create the chart, the teacher will listen for students to explain different ways 5 can be decomposed. The teacher can ask, "How do you know?" to prompt students to defend their answers by demonstrating their understanding with a count. The teacher can also challenge students by asking, "Is there more than one way to make 5?" "How can there be more than one way, 5 is just one number?" This will prompt students to "explain" or "teach" the teacher all the ways to make 5.

    3. As students complete their self-portrait with 5 buttons (step 5), the teacher can assess their understanding of the concept by looking for the student's ability to create a set of 5 buttons and explain how they decomposed the number using 2 colors.

    Variation Tips

    This activity can be done with any number 2-10 depending on student needs.

    During STEP 3: If available in your classroom, use a number balance or an online number balance (linked) to demonstrate the equality of each pair of numbers to 5 (ex: 5 on one side of the number balance, 4 and 1 on the other side to demonstrate the equality of the two sets of numbers.)

    During STEP 5: Students who need an additional challenge can draw friends in their picture, illustrating each person with a different way to decompose 5.

    During STEP 5: Students who need an additional challenge and have demonstrated a firm understanding of decomposing 5 can be given a number larger than 5 to decompose.

    Background and Preparation

    Background / Preparation

    Prepare video on a technology device.

    Prepare chart paper and supplies (step 3).

    Prepare paper and art materials for students to draw (step 5).

    Digital Tools / Resources