Answers and brief teacher note
Before using: check that the pupil can name units through thousands and show why 1 hundred = 10 tens (then 2 hundreds = 20 tens). If not, return to unit grouping with the teacher before using these pages.
Use: model with the equal-sized unit cells, ask every pupil to show or write an exchange, and check that the total stays unchanged. Use the worked pages and practice in an order and at a pace that suit the pupils. Fade the diagram and prompts as responses become accurate.
Feedback: if tens are added without removing a hundred, compare both totals. If a pupil keeps an unchanged but equal representation, clarify the exchange instruction before inferring a unit difficulty. If counts are joined as digits, ask what each group is worth.
Fresh retry after correction: 3 thousands, 2 hundreds, 11 tens and 9 ones = 3319. Ask the pupil to explain the retained units; record prompting.
Practice key: A 343; B 2565; C 17 tens; D 11 tens; E 5130; F no, it is 2646. Sam has lost 10 tens (100).
Independent explanation: put the teaching pages away. Ask: “7 thousands, 1 hundred, 15 tens and 4 ones. What is the number? Explain why.” Answer: 7254; 7000 + 100 + 150 + 4. A correct numeral alone does not show which strategy was used.
Rechecks: use online Form A after teaching and Form B on a later day, with worked pages hidden. Record the teaching date and any reading or mathematical help. Several days is a practical starting interval, not a fixed rule. Reusing either form gives familiar-item evidence.
Next step: independent success → reduce support and revisit later; errors → hear a fresh explanation and adjust the teaching; mixed evidence → confirm the need; no participation → arrange an opportunity, not a zero score. Five correct answers do not prove complete mastery.
Aide preparation: rehearse the 3422 exchange and one likely error with the teacher. Return to the teacher if unit meanings remain unclear. No physical blocks are required.
Online keys: Form A: B, C, D, A, C. Form B: A, D, B, C, B. Full option explanations are separate from pupil checks.