# Day 55 — Design a ten tool

**25 minutes · AC9MFN01 and AC9MFN04 (partial) · educator review pending**

**Success:** Child uses or directs construction of a reusable ten-frame with two rows of five boxes, tests it with ten counters, and records ten in two formats. Building the frame is a design activity; the mathematics evidence is in using it accurately.

**Prepare:** the child's earlier tool from [integrated Week 11](../../../term-2/week-11-ten-ways-to-see.md), if one exists; pre-cut card or reusable paper, thick pen/tape, [reference frame](ten-and-share.svg), ten counters, T06/T12 and a frame with one deliberately missing box. Adults handle any sharp cutting; a ready-made mat is an equal route. This lesson checks and extends an earlier design rather than asking every child to make a second board.

1. **Retrieve, 3 min.** Show yesterday's 8/2 or 3/7 split. Ask, “How could a frame prove the whole is ten?”
2. **Model, 5 min.** Point to two rows of five on the reference. Say, “A good counting tool has ten spaces. I can check the spaces before I use them.” Count boxes, then counters, separately. Show the nine-box faulty frame and ask what needs fixing.
3. **Design and test, 10 min.** If the child's existing tool has two rows of five boxes, audit and reuse it. If its layout differs, compare it with the prepared two-row frame; the child may adapt their own tool or use the prepared frame. If no earlier tool exists, pairs draw or direct ten boxes on reusable card. Test T06 (8/2) or T12 (3/7): put each part in a separate region of the two-row frame and confirm it fills ten boxes. One partner audits the box count, the other audits counter count. Teacher observes three focus learners and repairs a faulty frame with them.
4. **Fresh check, 4 min.** Give a new ten loose counters. Child fills their frame and gives another representation: numeral `10`, ten marks or a two-part split. The format is their choice.
5. **Close, 3 min.** Store tools for Week 12. **Key:** two rows × five boxes = ten boxes; T06 8/2 and T12 3/7 make ten; a nine-box mat must gain one box before it is a ten-frame.

**If the child puts several counters in one box:** Rehearse one-to-one placement with five boxes, then complete both rows. **Access and record:** Pre-drawn, raised or digital frame is valid; the child may direct every placement. Note the actual representation used and whether ten was inferred from the structure or counted.