The decomposition of numbers sounds WAY more complicated than it really is. Let's break it down into smaller parts – LITERALLY.

Teaching decomposing numbers in kindergarten math can be a challenging task, but when done right, it can be both helpful AND fun. Shall we get right to it then?

KINDERGARTEN MATH

Why is the decomposition of numbers important for kindergarten students?

Number decomposition is a fundamental mathematical skill that lays the groundwork for more complex concepts. Understanding how to break down numbers into smaller parts enables young learners to grasp the concept of addition and subtraction. For kindergarten math students, this skill is crucial as it fosters number sense, which is the ability to understand, relate, and connect numbers in various ways.

Children learn that numbers can be represented in multiple forms by decomposing numbers, facilitating a deeper understanding of their relationships. And who doesn't want that, right?

Why is composing and decomposing numbers taught in kindergarten math?

Math in kindergarten lays the groundwork for students. Introducing number decomposition at an early age prepares students for more advanced mathematical concepts they will encounter in later grades.

Additionally, teaching the decomposition of numbers helps students develop problem-solving skills. When children encounter mathematical problems, the ability to decompose numbers allows them to approach challenges from different angles, enhancing their analytical thinking.

It encourages them to see numbers not just as isolated figures but as components that can be manipulated and combined in numerous ways. This flexibility in thinking is essential for their growth as mathematicians and supports their confidence in tackling future math-related tasks.

Okay…so now we know why teaching this complex idea of decomposition of numbers in kindergarten math is essential…but HOW DO WE MAKE IT FUN?? THEY'RE 5!

Decomposition of Numbers

I teach kindergarten in a public elementary school in Nashville, TN. We start introducing composing and decomposing numbers around the beginning of November. We have already introduced simple addition and subtraction by this point. What I noticed was that my kinders were making the act of decomposing numbers WAY more complicated than it actually is. So, I developed a five-day roll-out to help them gradually build up to the connection between the two skills.

Click to see Decomposing Numbers to 10 – Ten Little Leaves readers, craftivities, and slides. We start with whole group slides, and then we move to scaffolded booklets where they can practice. Finally, there are fun craftivities for them to continue to explore decomposing numbers to ten independently.

After my students are exposed to the decomposition of numbers, we typically head into a week-long Thanksgiving break. When they come back, we need to re-introduce this new skill and try to solidify the concepts of composing and decomposing numbers. However, if you have ever taught kindergarten in the month of December…well, let's just say if you know, you know.

If you are new to teaching kindergarten – trust me when I say repetition is KEY in the chaos.

This is why I created a gingerbread cookie-themed version of what they were already exposed to with Ten Little Leaves!

Decomposing Numbers With Ten Little Cookies

I’ve found that using the same structure helps them remember what skill it is we’re working on, and also boosts their confidence a bit. You can roll this out however you wish, but here is how I use it in my classroom in December:

• DAY 1 – I start by displaying the TEN LITTLE COOKIES presentation (the circles and stars version.) Slowly, we talked through each slide, and I let them come up and fill in the number sentence. Even though the numbers are already IN the story – it was necessary and good practice for them to place those same numbers into a number sentence. (This is where some of them try to make it harder than it is – so the repetition really helps!)

• DAY 2 – I gave them each a cookie sheet and a set of 10 circle cookies and 10 star cookies.
  • They could do any combo they wanted, but the total has to be 10. (the extra cookies they always ask if they can keep to color and glue to their free write journal :))
  • I then had them cut the cookies out and glue them onto their cookie sheet.
    • Then they told me the number sentence, and as I gave them the part of the activity to write the number sentence – I pointed and read their sentence to them. They were all able to correctly place the numbers in. This has been a struggle in the past. They may have four circles and six stars, but then still wrote 5 + 5 = 10 on their number sentence

• DAY 3 – I used the B&W booklet for the circle and star cookies. I started whole group and modeled the first page. Then, I let them work on them individually or with partners.

• DAY 4 – I displayed the TEN LITTLE COOKIES presentation (gingerbread cookies running off the pan version). This shows a different way to decompose – and since the cookies are “leaving,” – it offers them a different way to visualize things.
  • We complete this whole group. BONUS: The repetitive nature of the reading passage provides a great opportunity for it to be student-led. Talk about a confidence builder! I had kids begging to have a turn – so much so that we did it twice!

• DAY 5 – I used the B&W booklet for the gingerbread men running away. I started whole group and modeled the first page. I then asked them to work individually this time so I could really gauge where they were.
  • There are two levels of this booklet. One includes the numbers in the reading passage – but allows them to complete the number sentence. The second leaves out the numbers in the reading passage – allowing them to use the picture to complete the work.

***You do NOT have to use every activity – or stretch it out for 5 days. Use any or all parts as it suits you and your students best!

Math In Kindergarten

Math in kindergarten is definitely more advanced than when I was five years old. That's why incorporating playful methods to teach a skill such as the decomposition of numbers encourages active participation. Young learners thrive in settings where they can engage physically and socially. Activities that involve movement or collaboration not only enhance their understanding of composing and decomposing numbers but also promote teamwork and communication skills.

For more kindergarten math – check this out! And This!