Home » Worksheets » Addition » Decomposing Numbers within 20 1st Grade Math Worksheets

Decomposing Numbers within 20 1st Grade Math Worksheets

Download Decomposing Numbers within 20 Worksheets

Click the button below to get instant access to these premium worksheets for use in the classroom or at a home.

Download Now

Edit Worksheets

This worksheet can be edited by Premium members using the free Google Slides online software. Click the Edit button above to get started.

Download free sample

Not ready to purchase a subscription yet? Click here to download a FREE sample of this worksheet pack.


Some things are created because of the combination of other things! Numbers do the same! A number is a combination of other numbers. How does it happen? This worksheet will help you!  

Decomposing numbers means to break down numbers into their sub-parts.
It means breaking a number into tens and ones.
The opposite of decomposition is composition – to put parts back together.


12 can be split up to 7 and 5.

Decomposing Numbers within 20 Worksheets

This is a fantastic bundle which includes everything you need to know about Decomposing Numbers within 20 across 15+ in-depth pages. These are ready-to-use Common core aligned Grade 1 Math worksheets.

Each ready to use worksheet collection includes 10 activities and an answer guide. Not teaching common core standards? Don’t worry! All our worksheets are completely editable so can be tailored for your curriculum and target audience.

Resource Examples

Click any of the example images below to view a larger version.