Take two or three hands-up answers for the rough estimate first (roughly €1,000), then ask where a rename might be needed. Keep it to estimating and predicting — don't solve it yet, this hook just gets pupils thinking ahead.

First one, 3,524 − 1,287 = 2,237: the warm-up, two ordinary renames, no zeros. Units 4 take 7 too small, so 4 becomes 14 and the tens drop by one; then rename in the tens. Same trade, one column further along.

Second, 4,003 − 1,576 = 2,427: units 3 take 6 too small, but tens and hundreds are zero. Ask what we can take from a zero before revealing. Borrow keeps moving left until it reaches the 4 thousand; each 0 it passes becomes 9.

Third, 5,000 − 2,648 = 2,352: the key one. Ask where the borrow starts. It travels all the way from the thousands; hundreds and tens become 9, units become 10, then subtract.

Model the add-back explicitly so pupils know exactly how to reverse the operation. Say it aloud: 'the answer plus the number we took away should rebuild the number we started with.' Work the sum on the whiteboard together to confirm the total is 5,000. Keep this brief — it is a proof habit, not a new method.

This round is for talking it through together — pupils take turns at the board and the class agrees or corrects out loud. Reveal each sum on the interactive as it is worked, rather than showing all four at once.

Call one pupil up per problem. Have them stack the numbers, then work each column from the right, marking a borrow note where a column is too small. The rest of the class predicts whether each column needs a rename before the pupil works it.

Watch for the common slip on 6,300 and 7,000: pupils try to take from a zero directly. Revoice: 'there's nothing in the tens to take, so we go one more column left.' Rotate four pupils across the four problems.