Primary Type: Lesson Plan
Status: Published
This is a resource from CPALMS (www.cpalms.org) where all educators go for bright ideas!
Resource ID#: 34910
Decompose That Teen Number!
The students will receive explicit instruction from the teacher on the definition of decomposing a number and how to represent a decomposition with
manipulatives, drawings, and equations. The students will use linking cubes to reflect numbers from 11-19, and to show their understanding of how to
decompose a number. Students will record decompositions as an equation.
Subject(s): Mathematics
Grade Level(s): K
Intended Audience: Educators
Suggested Technology: Document Camera
Instructional Time: 40 Minute(s)
Freely Available: Yes
Keywords: decomposing numbers, decompose, place value, tens, ones
Instructional Design Framework(s): Direct Instruction
Resource Collection: CPALMS Lesson Plan Development Initiative
LESSON CONTENT
Lesson Plan Template: General Lesson Plan
Learning Objectives: What should students know and be able to do as a result of this lesson?
Students will decompose numbers from 11-19 into tens and ones
Students will record a decomposition in drawings and equations.
Prior Knowledge: What prior knowledge should students have for this lesson?
Students should know basic math vocabulary: tens, ones, place value, equations.
Students should know that two tens equal 20.
Students should know how to write basic math problems prior to the lesson (for example 2+3=5).
Guiding Questions: What are the guiding questions for this lesson?
How do we know how many tens a number contains?
How can we find out how many tens or ones a number contains?
What types of things can we use to show place value of tens and ones?
Why do we need to know place value?
What are ways to write equations?
Teaching Phase: How will the teacher present the concept or skill to students?
The teacher should review the concept of writing an equation to symbolize a math problem. Give the following example: there are 4 apples in my shopping bag. I
put 4 more apples in the bag.
Ask a student to draw an illustration of the 4 apples and then the 4 more on the board or a document camera.
Ask a student to model writing the equation 4+4=8 for the class to see.
Provide a hook for students by writing the equation 11=10+1 on the board.
Tell the students they are going to figure out what that means.
Pass out linking cubes and have the students use the linking cubes to show a train of ten cubes and another train of one.
Explain to the students that this is 10+1=11.
Tell students, "Now we are going to switch it to decompose the number 11. To switch it we are going to write the number 11 first and show the other two trains
page 1 of 3 with the missing parts to the right of the equal sign. The equation would now be 11=10+1."
Assign a partner (shoulder partner) to each student. The Formative Assessment can be a guide for assigning partners (matching strong students together or placing
strong and struggling students together).
Guided Practice: What activities or exercises will the students complete with teacher guidance?
The teacher will call on a few students to bring up their linking cubes and provide examples of tens and ones.
Students will describe what the numbers are each time they make a train.
The teacher will then introduce the vocabulary, compose and decompose, and use pictures or drawings to show other examples on the board.
To practice, the teacher will give numbers for the students to make (a ten and more ones).
Have the students complete this activity for 3-4 different numbers from 11-19.
Independent Practice: What activities or exercises will students complete to reinforce the concepts and skills developed in the
lesson?
The students will be given index cards to write down their own choice of numbers from 11-19.
Student will decompose each number with the cube trains and write an equation to represent the decomposition.
The students should write at least 4 decomposing equations and be able to share how they got their answers.
Closure: How will the teacher assist students in organizing the knowledge gained in the lesson?
The students will share their equations with their shoulder partners and describe how they got their answers.
A student will share with the class how to decompose the numbers 11 - 19 and write an equation.
The teacher will administer the Summative Assessment.
Summative Assessment
Students will create a visual representation to show their understanding of place value (tens and ones).
For example, the students may be asked to draw cube trains to show 10 and a specific number more. If the teacher says show 16, then the student would draw a
10 cube train and another train showing 6 more. They will then need to write the equation 16=10+6.
The teacher will need to give at least 3 numbers for the students to show the understanding of tens and ones place. Student should also be able to provide the
correct equation written in the form shown above.
Formative Assessment
Before the lesson, provide students with a piece of paper and a crayon or pencil. Tell them that there are 3 cats sitting on a fence and 2 joined them, so now there
are 5 cats in all.
Ask students to draw an illustration of 3 cats sitting on the fence and then add the other 2.
Ask students to write an equation to show this.
Use the student responses to determine students' readiness to learn how to decompose number numbers from 11-19. Provide remediation for students who do not
have the prerequisite prior knowledge.
Feedback to Students
The teacher will monitor the students during the lesson, asking questions to probe their thinking and scaffold the task of students who need assistance. Use the
Guiding Questions section for suggested questions.
Students should be encouraged to explain their work.
ACCOMMODATIONS & RECOMMENDATIONS
Accommodations:
Provide different materials including straws.
Pair struggling students with stronger students.
Provide written equations to decompose or provide previously made trains to write equations for.
Provide extra support with questions that will elicit and guide thinking.
Provide English Language Learners with extra support for definitions and examples of unfamiliar vocabulary words.
Shorten the assignment or provide extra time.
Extensions:
Provide pretzel sticks and Cheerios to show understanding of tens and ones, using one pretzel stick as a ten and Cheerios as ones.
Allow students to attempt to decompose numbers 20-29.
Suggested Technology: Document Camera
Special Materials Needed:
Linking cubes (or alternatives, if necessary)
Class set of index cards
Any differentiated materials for accommodations or extensions
A document camera may be helpful, but is not required
Further Recommendations: Eleven and twelve do not sound like sixteen, seventeen, eighteen, etc. Give these number words extra attention with respect to their
meanings, as their meanings may not be intuitive for students. This is especially crucial for English Language Learners.
Additional Information/Instructions
By Author/Submitter
This resource is likely to support student engagement in the following the Mathematical Practice: MAFS.K12.MP.4.1.
page 2 of 3 SOURCE AND ACCESS INFORMATION
Name of Author/Source: Anonymously Submitted
Is this Resource freely Available? Yes
Access Privileges: Public
License: CPALMS License - no distribution - non commercial
Related Standards
Name
MAFS.K.NBT.1.1:
Description
Compose and decompose numbers from 11 to 19 into ten ones and some further ones, e.g., by using objects or
drawings, and record each composition or decomposition by a drawing or equation (e.g., 18 = 10 + 8); understand
that these numbers are composed of ten ones and one, two, three, four, five, six, seven, eight, or nine ones.
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