As many of our readers know, I am not a huge fan of the Common Core State Standards as they are written.  For now,  the CCSS are with us and we must creatively work with the standards to help our children learn and document progress toward achievement.  

Decomposing the Numbers 1-10

CCSSI K.OA.3 states “Decompose numbers less than or equal to 10 into pairs in more than one way, e.g., by using objects or drawings, and record each decomposition by a drawing or equation (e.g., 5 = 2 + 3 and 5 = 4 + 1).”

Most young children do not, naturally, think in terms of differing pairs that make up the same number.  In decomposing numbers, discuss with the children that pairs are simply TWO groups of numbers (objects) that add up to the SAME number.

Materials needed for using the Fall Printables (linked below):  pumpkin seeds (or crayons/markers) and one printable for each child of the number(s) that are being introduced.

  Have the children count out real pumpkin seeds (or draw small circles to represent pumpkin seeds) to show the number of items needed in each box on the printable.  Have the children verbally count out loud as they place the pumpkin seeds on the counting mats.  In each row, there are two boxes for each of the two groups of numbers (objects) that, when added together, will make the desired sum.

When decomposing numbers, there is a pattern.  Making vertical number lines will help your children visualize the pattern.  Our 4 yr. olds could see the pattern and found the same pattern works to decompose any number into pairs.  Cut apart the individual cards and place them in sequential order on a table or the floor.  In the photo, our kids were working with the Number Seven Printable.

DECOMPOSING THE NUMBER 7: What is the pattern when decomposing any number into sub-parts?

For a game to play:  give the children 7 pumpkin seeds in a plastic cup.  Tell the children they must give all of their pumpkin seeds away, but they have to divide the seeds between 2 people (peers, teachers, parents, etc.).  Have the children count/write how many seeds they gave to each person and find it on the vertical number lines.   Have the children write/draw the equation on a separate sheet of paper.  Change the number of seeds in the cups as different numbers are decomposed/introduced.

To document progress, have the children cut apart the cards and use them in math journals.  In the photo below, our kids used Wikki Stix to represent the seeds in their journals.  Have the children write the “equation” below each of the cards.

Documenting Number Decomposition in Math Journals

To view/print the Fall-themed Numbers 1-10 for decomposing, click the links below.

Decomposing One

Decomposing Two

Decomposing Three

Decomposing Four

Decomposing Five

Decomposing Six

Decomposing Seven

Decomposing Eight

Decomposing Nine

Decomposing Ten

For additional Fall Learning Activities for Preschool and Kindergarten, see the Fall Theme at:  The Preschool Toolbox Blog!


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