First Grade

Composing and Decomposing Numbers

Empowered Learner and Computational Thinker


The Starfall Compose & Decompose numbers game is a great option for practicing adding, place value for ones and tens, and number identification in a steady, consistent format. This game is a great option for independent center practice, whole group instruction or small group instruction. The game format is slow and provides explicit explanations for students to grasp each step. If students misplace straws the game automatically shows them where they belong for self-correction.

Students will:

  • Be able to identify whole numbers
  • Be able to identify ones and tens place value
  • Be able to compose numbers with place value

Vocabulary Words:

  1. Compose: To compose in math is putting a number together using its parts. 

  2. Decompose: To decompose in math is to break down numbers into parts.

  3. Add: To add is to join two numbers together.

  4. Subtract: To subtract is to take away from another to see the difference

  5. Place Value: Place value is the value represented by a digit in a number on the basis of its position in the number.

To prepare for this lesson:

See the Accommodations Page and Charts on the 21things4students website in the Teacher Resources. 

Directions for this activity:

  1. Have the students begin the activity Starfall’s Composing & Decomposing numbers.

  2. Provide manipulatives for students to use as an additional visual and tactile resource through this activity.

  3. Make sure your computer speakers or headphones are connected for the best game quality. 

Student Directions for this activity:

  1. Listen to the number the candy machine says and locate the visual whole number on the screen.
  2. Count how many pieces of candy the machine has provided.
  3. Move candy pieces to the correct place value space (tens or ones).
  4. Complete this task three times to finish the game. 

Different options for assessing the students:

  • Observations
  • Check for understanding
  • Ask students to teach one another the process of composing or decomposing numbers.

MITECS: Michigan adopted the "ISTE Standards for Students" called MITECS (Michigan Integrated Technology Competencies for Students) in 2018.

Empowered Learner
1a. Students develop learning goals in collaboration with an educator, select the technology tools to achieve them and revise the learning process as needed to achieve the goal.
1c. Students use technology to seek feedback that informs and improves their practice and to demonstrate their learning in a variety of ways.

Computational Thinker
5c. Students break problems into component parts, extract key information, and develop descriptive models to understand complex systems or facilitate problem-solving.

The app can be located at: 

Requires iOS 5.1.1 or later. Compatible with iPhone, iPad, and iPod touch.

The app is free to download and compatible with iPhone, iPad and iPod Touch. This particular game is free without membership. Additional games and options are available through Starfall with a membership. Membership options include Home membership for $35.00/year, Teacher membership for $70.00/year, Classroom membership for $150.00/year or School Membership for $270.00/year. 


What is Composing and Decomposing Numbers?


Practice reading - order, tens, ones, great job!

Practice adding, subtraction, place value and number recognition.

This task card was created by Lisa Cleveland, Jackson ISD, June 2020. Updated November 2023.