25 minutes · AC9MFN05 (practical subtraction and quantification); partial practice · educator review pending
Success: The child distinguishes the number remaining in a named location from the total number of objects across two locations after a move.
Prepare per pair: eight safe reusable classroom blocks or cards, a floor mat, storage tray, start/change/now strip and scene card 6. The teacher can use an actual class tidy-up with approved materials; no personal belongings are needed.
- Retrieve, 3 min. Count eight blocks on the floor mat. “Are all eight here before we start?”
- Model, 6 min. Move three into the tray. Say, “Eight blocks were on the floor mat. I moved three into storage. Five remain on the floor mat. If I ask for all blocks in both places, there are still eight.” Count five on the mat and then all eight across mat plus tray; point to the different question each count answers.
- Guided game, 9 min. Partners enact eight sports cones, three stored; nine parcel cards on a desk, four moved to a shelf; or ten music-shaker cards out, six packed away. For each, ask both “How many remain here?” and “How many exist across both places?” Swap roles.
- Fresh try, 4 min. Give seven objects on a desk mat; child moves two to a tray. “How many remain on the desk? How many are there altogether across both places?”
- Check, 3 min. Show the eight-block model again. Key: 8 start, 3 moved, 5 remain on the first mat, 8 total across both; 9 − 4 = 5 on desk with 9 total; 10 − 6 = 4 out with 10 total; independent 7 − 2 = 5 on desk, 7 total.
If the child answers eight to both questions: Mark the floor-mat boundary and count only there, then sweep around both locations for the total. If the child says moving three “makes three new blocks,” compare the same objects before and after; none were created.
Access and record: Use distinct raised mat/tray edges, grippable pieces, a visual and spoken route, or child-directed adult movement. Record both named-set and all-place totals, plus exact explanation and cues.