# Day 74 — Two parts build one whole

**25 minutes · AC9MFN04 · educator review pending**

**Success:** Child starts with two disjoint parts, combines the actual objects into one whole up to ten, and names the whole. A small visible part may be subitised where accessible; the whole is checked by counting.

**Prepare:** separate A/B mats, an empty whole mat, six and three counters for [P11](print-aids.md), nine and one for P12, and a fresh A4/B3 set kept out of view. Do not place a second copy of the parts into whole.

1. **Retrieve, 3 min.** From yesterday's whole-ten problem, show A seven/B three. Ask how to bring the whole back.
2. **Model, 5 min.** Start with P11's six in A and three in B. Say, “The whole is empty now. I move each part into it; I do not copy them.” Move all nine across, one at a time. Count nine and show that A/B are empty.
3. **Composer game, 10 min.** Partners compose P11 then P12. One moves, the other checks no counter was left or duplicated. Reverse the process by repartitioning the new whole into the original parts. Teacher asks three focus learners which direction they are doing: parts to whole or whole to parts.
4. **Fresh check, 4 min.** Present four counters in A and three in B. Child moves all into whole and counts seven, then shows 4/3 again if time.
5. **Close, 3 min.** Ask how we know a part was not counted twice. **Key:** P11 6+3=9; P12 9+1=10; fresh 4+3=7.

**If the child leaves originals on the part mats and adds new counters to whole:** Remove spare counters; move the originals physically, and check the part mats are empty. **Access and record:** Adult moves under child direction, tactile spaces, sign/AAC and verbal labels are valid. Note whether the learner used small-group recognition, one-to-one counting or support.