Free Printable Number Decomposition Worksheets for Class 1

In first grade, the focus shifts to place value. Students learn to decompose two-digit numbers, specifically understanding that numbers from 11 to 19 are composed of one ten and some further ones. This is a critical step toward understanding the base-ten number system.

The "make a ten" strategy is central. When adding 8 + 5, teach students to decompose the 5 into 2 and 3. They can then add 8 + 2 to make a friendly 10, and add the remaining 3 to get 13. Using ten frames and number bonds helps make this abstract strategy concrete.

Many first graders struggle to unitize, meaning they have difficulty seeing a number like 14 as both a single group of "fourteen" and as a composite group of "one ten and four ones." Consistent practice with place value blocks and ten frames helps bridge this conceptual gap.

You can assign these worksheets in the format that best suits your lesson. Print the PDF for a small group activity with base-ten blocks, or assign it as a digital quiz on Wayground for independent practice. Both formats use the same problems and come with a complete answer key.

This topic directly follows the Common Core curriculum progression. After learning to decompose numbers up to 10 in kindergarten, first graders apply that part-whole understanding to the structure of teen numbers, seeing them as a bundle of ten plus some ones. This is their first formal step into place value.

For digital assignments, use Wayground's Read Aloud feature to support emerging readers and the Reduced Answer Choices option for students who are easily overwhelmed. When printing worksheets, you can create alternate versions with larger fonts or wider spacing to help students who need clearer visual presentation.