# Put parts together

Represent parts and a whole and connect joining to addition.

## Try it

1. Put counters in each part.
2. Join them. How many altogether?
3. Draw and tell what happened.

Use the part-part-whole mat.

- 2 red cups and 1 blue cup. How many cups?
- 3 children are here. 2 join them. How many now?
- 4 blocks are here. Add no blocks. How many now?

Draw the parts and the whole. Tell how they fit together.

## Your materials

[Open the pupil workbook PDF](/files/c385c4cae385f0f332fd1c00d8e3dba4e2a5838fae4774b70df25e42e950768e). Use pages **13, 41, 42, 44**.

Part-part-whole mat and counters.

## Teacher lesson plan

### Learning goal

Represent parts and a whole and connect joining to addition.

### Before teaching

Can count the selected collections and recognize that the last count word gives the total.

### Model

Place 2 counters in one part and 1 in the other. Move them into the whole: 3. Say “Two and one make three.” Connect the action to 2 + 1 = 3. Explain equals as the same amount, not a signal meaning “write an answer.”

### Guide, then apply

Model the pupil stories with counters and drawings before writing equations. Separate the same whole into different parts. Include an empty part after zero is understood.

### Interpret the response

Practice results: 2 + 1 = 3; 3 + 2 = 5; 4 + 0 = 4. If the child counts a moved counter again in both part and whole, physically separate the phases and recount the whole once.

### Support

Use concrete action and spoken explanation without requiring equation writing. Point to each part and its role.

### Extend when ready

Find different decompositions of a whole and explain what remains constant. Move toward K.OA.2 word problems within 10 when the smaller examples are understood.

### Fresh check

Tell “There are 1 red cup and 3 blue cups. How many cups?” Ask for a model and explanation using a different arrangement.

[Teacher plans PDF](/files/1f4985652f45f6b19ef743d7b27765081e2d637d0a001670faa74e59383c736a): page 13. Record exact support and revisit the idea later.

## Keep learning

[Next in this path: Take away and explain](/agent/docs/tk-lesson-subtract) · [Choose a learning path](/agent/docs/tk-learn)

## Publication details

| Field | Value |
|---|---|
| Material | Classroom lesson |
| Learning path | Numbers and reasoning |
| Lesson | 12 |
| Learners | California TK, ages 4–5 |
| Setting | Full classroom |
| Pacing | Teacher selects from observed prerequisites |
| Author | Arcomm |
| Edition | First edition, 2026-09-08 |
| Format | Markdown |
| Evidence status | Original synthesis; not outcome-validated |

## Sources and dates

- [CDE: Mathematics](https://www.cde.ca.gov/sp/cd/re/documents/ptklfmathdomain.pdf): current PTKLF edition. Retrieved 2026-09-08T03:44:00.628834+00:00.
- [CDE: Kindergarten Mathematics Framework](https://www.cde.ca.gov/ci/ma/cf/documents/mathfwkindergarten.pdf): K.CC.5 and K.OA.1–5; kindergarten extensions. Retrieved 2026-09-08T03:44:00.628834+00:00.

[Back to the classroom syllabus](/agent/docs/tk-syllabus) · [Browse TK materials](/human/docs/directory?subject=society%2Feducation%2Ftransitional-kindergarten)

## Revisions

[Revision history](/agent/docs/tk-lesson-join/history)