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Teaching Composing and Decomposing Numbers to Kindergarten

Understanding the number system is the bedrock of math, and teaching young children that they can partition numbers from a whole to parts, and then recompose that number is one of the first steps in math operations. Using popcorn makes everything more fun!

Students need to have a firm foundation of number bonds and building and breaking numbers before beginning work on addition and subtraction. I like to begin with demonstrating using this FREE circus number bonds work mat to show how to decompose and compose numbers. It’s available as a free download from my Teachers Pay Teachers store.

free composing and decomposing kindergarten math activity

If possible, project this to a whiteboard and use magnetic counters to show the students how to break numbers. Start by taking a card with a number written on it. Put this many counters up in the elephant’s circle.

Free kindergarten decomposing and composing numbers activity

Count all the counters together as a class. Move some of the counters to the lion, and the rest to the sea lion. Count how many the lion has. How many does the sea lion have? Who can remember how many counters the elephant had to begin with? Are there still that many counters all together now? Count and check. Keep playing this as a whole class, or in small groups for reinforcement until you are sure that everyone understands that the total number does not change, but it can be broken up (decomposed) into smaller numbers. Give everyone the opportunity to come and share the elephant’s counter ‘popcorn’ to the lion and the sea lion.

When you are confident that everyone understands what to do give each student their own work mat and popcorn manipulatives (or use counters or real popcorn!).  Start by drawing one of the popcorn cards and place that number of popcorn manipulatives onto the circle under the elephant. 

Tell the students that the elephant can break up the number of pieces of popcorn between his two friends.  Have the children move some of the popcorn to the lion and the rest to the seal and discuss the different ways they found to share.  Then tell the students how many popcorn kernels to give the lion and have them find how many is left for the seal.  Practice this frequently – it is a great way to start every math lesson and review at the end. 

As children become more proficient in decomposing numbers, have them play this game and record their work on these recording sheets.  After a period of practicing physically decomposing numbers and building numbers introduce recording number bonds in the form of number sentences.

Composing and Decomposing worksheets for kindergarten

Students will need lots of practice!  Revisit the concept sheets regularly by placing them in your math station rotations (once you have taught children how to use it, it is a great reinforcement math center!).

Looking for more practice and hands-on activities? Check out these Kindergarten Composing and Decomposing worksheets and centers from my Teachers Pay Teachers store!

I hope using this fun, free resource makes your teaching of decomposing numbers easier!

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Use these fun free downloads and popcorn to introduce your kindergarteners to decomposing numbers.  Includes a recording sheet - learn more!
Use these fun free downloads and popcorn to introduce your kindergarteners to decomposing numbers.  Includes a recording sheet - learn more!

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