# RC-PV01 item review — precision refinement

Resource/recheck version: 2026-09-23-precision-v3. The five recheck questions are unchanged from visual-v1; the current revision changes teaching wording, equality orientation, the zoom cue and pupil navigation. Practice and adult key are unchanged from visual-practice-v2. Intended skill: read/write three- and four-digit whole numbers with zero placeholders; match number words, unit parts, numerals and expanded forms. Prerequisite: recognise thousands, hundreds, tens and ones. This is the approved narrow PV01 scope, not full Years 3–4 place value. Reference inputs: `board/11.6/RESOURCE-BRIEFS.md`, current pilot source and the supplied book chapters.

All prompts/options below are rendered in the separate `RECHECK.html`; no diagrams, coloured unit cues, worked example or key are included in that pupil file. JSON follows the current objective/question shape (`questions`, `n`, `type`, `expression`, `question_prompt`, `report_prompt`, four `options`, zero-based `correct`, three `distractors`, declared pattern tags). RC-PV01 is a new recheck identity, not a new curriculum identifier. It is not loaded into the fixed 25-question bank.

## 1 · One empty place: words → numeral

**Which number is two thousand, eight hundred and six?**

A. 2086 · B. 2860 · **C. 2806** · D. 286

Independent solution: 2×1000 + 8×100 + 0×10 + 6 = 2806. One correct option.

- A puts the eight hundreds into tens: possible column confusion.
- B puts the six ones into tens: possible packing-left pattern.
- D omits the empty tens place and reduces the magnitude.

Correct selection supports matching this word form to its numeral. A pupil can also eliminate three-digit D by length; the remaining three four-digit options require further discrimination. It does not establish unsupported numeral construction or a particular strategy.

## 2 · Two empty places: words → numeral

**Which number is nine thousand and four?**

A. 9040 · **B. 9004** · C. 904 · D. 94

Independent solution: 9×1000 + 4 = 9004. One correct option.

- A makes the four into four tens.
- C gives nine hundreds, not nine thousands.
- D drops both empty places.

Correct selection supports the two-gap match. Knowing that the answer needs four digits eliminates C/D; it does not distinguish A/B. This is a deliberate representational contrast, not a proven diagnosis of either wrong answer.

## 3 · Terminal zero: expanded parts → numeral

**Which number is 6000 + 300 + 20?**

A. 6302 · B. 632 · C. 6032 · **D. 6320**

Independent solution: 6000 + 300 + 20 + 0 = 6320. One correct option.

- A makes the two tens into two ones.
- B drops the empty ones place and changes all unit values.
- C shifts the hundreds/tens parts into lower places.

Correct selection supports retaining the terminal ones zero. Summing correctly is a valid alternative to constructing a chart. No diagram or coloured cue supplies the option.

## 4 · Numeral → words

**Which words match the number 4050?**

**A. four thousand and fifty** · B. four hundred and fifty · C. four thousand five hundred · D. forty-five

Independent option values: A=4050, B=450, C=4500, D=45. All distinct; A alone equals the target.

B reduces the thousands to hundreds; C makes the five tens into five hundreds; D drops the zero places. Correct selection supports reading this particular numeral. Number-word familiarity and reading access can affect performance; record support rather than asserting a place-value misconception from language alone.

## 5 · Transfer: named units → expanded sum

**A number has 7 thousands, no hundreds, 8 tens and no ones. Which sum makes that number?**

A. 7000 + 800 · B. 700 + 80 · **C. 7000 + 80** · D. 7000 + 8

Independent target: 7×1000 + 0×100 + 8×10 + 0 = 7080. Options evaluate to 7800, 780, 7080 and 7008; only C matches.

A promotes tens to hundreds; B reduces thousands to hundreds; D makes tens into ones. A correct response supports mapping units into a different response form. The explicit unit wording is part of the task, not evidence of unprompted explanation. This is near transfer, not broad mathematical generalisation.

## Cross-item interpretation and limitations

Keys: C, B, D, A, C. Four choices by default; no option position identifies every correct answer. Model/probe/practice/pilot target values are excluded from these five targets. Whole-number target values are 2806, 9004, 6320, 4050 and 7080; sharing individual digits or unit words is necessary for the intended skill and is not a copied item.

All wrong-answer explanations are hypotheses. Misreading, guessing, attention or language can produce the same selection. Q1/Q2 repeat the response form with materially different zero patterns; they are not duplicate/commuted questions. A perfect score shows five sampled selections, not independent construction, retention or full mastery. The separate fresh written prompt 5036 helps a teacher confirm construction without a supplied chart.

The broad `part-in-wrong-column` tag here can occur in different directions; it must not automatically merge with the existing pilot's narrower hundreds-in-tens interpretation. `RC-PV01 + tag` is the identity until a reviewed mapping is implemented. Pattern counts and app routing remain future Task 12.5 work.

## Schema and integration boundary

The grade validator hardcodes 16 questions and four answers per option position, so it cannot validate a five-item recheck unchanged. The bounded checker preserves its four-distinct-options, index, sequence and three-distractor checks for five questions, then exercises the existing `analyseStudentSection` function on synthetic correct/wrong/missing responses. This verifies local question/scoring compatibility only. It is not report-to-resource-to-recheck integration, production testing, an adult walkthrough or pupil validation.


## Visual practice A–D — instructional items, separate from the recheck

| Item | Full task and model | Independently solved answer | What it offers / limits |
|---|---|---|---|
| A | Make 3024. Line 3000–3040, ticks of 1; displayed jumps 3000→3020 and 3020→3024, second jump label missing. Complete 3000 + ___ + ___ = 3024. | Jumps 20 and 4; sum parts 20 and 4. | Connect pictured intervals and symbolic parts. Counting four intervals or using the supplied target is permitted practice support. +5 may reflect counting marks rather than intervals; confirm rather than diagnose. |
| B | Draw the jump to 3004 on the same 3000–3040 line; complete 3000 + ___ = ___. | Jump from 3000 to 3004; 4 and 3004. A single +4 arc or four +1 arcs reaches the same endpoint. | Pupil produces a representation with more support removed. A jump to 3040 may indicate unit/scale confusion or misreading. Accurate drawing is useful evidence but handwriting precision is not the learning goal. |
| C | Four thousand and eight. Chart provides 4 thousands and 8 ones, with hundreds/tens digits blank; write the number. | Chart 4,0,0,8; number 4008. | Makes both zero positions explicit. Supplied outer digits cue the four-place structure; this is not independent numeral construction. |
| D | Six thousand and thirty. Blank chart with four unit headings; complete 6000 + ___ = ___. | Chart 6,0,3,0; 30 and 6030. | Links language, a pupil-completed chart and sum with fewer supplied parts. 6300/6003 could signal misplaced units or language difficulty; explanation is needed. |

Full pupil models: FORMAT-PREVIEW.html#visual-practice; full adult answers: ANSWERS.html. No numeric practice-answer blanks are encoded as supplied answers in the charts. SVG accessible descriptions match the visible information. All four targets are distinct from the five recheck targets and the reserved 5036/8206 construction prompts.

The adult-only write-and-explain prompt is: “Write five thousand and thirty-six. Show what each digit means.” Solution: 5036 = 5000 + 0 + 30 + 6; 5 thousands, 0 hundreds, 3 tens, 6 ones. Accept correct labelled drawings, expanded sums or explanations, including omission of the zero term where its place in the numeral is preserved. Record help. A correct answer on this one example is not proof of general mastery or retention.