Give five seconds of quiet think-time before any hands go up, then take three hands-up answers — about half the class will say start with the thousands because that is how we read numbers. Do not reveal the right answer yet; that is what the lesson will show.

Walk each example aloud, one at a time. Pause between examples so pupils can predict the next column before the snapshot reveals it.

• Example 1 (4,738 + 2,569): trace each carry-1 as it lands. Ask 'where does the 1 go after 8 + 9 = 17?' before revealing. After the final answer, ask the class to name the destination columns and take a quick answer: 'tens, hundreds, thousands!'
• Example 2 (9,876 + 1,234): the regroup from the units triggers a regroup in the tens, which triggers another in the hundreds, all the way up. Pupils predict each carry in turn; you confirm. End by pointing at the lone 1 in the ten-thousands column — 'that 1 used to live in the thousands column'. Then ask the class to name the carry columns and take a quick answer: 'tens, hundreds, thousands, ten-thousands!'
• Example 3 (5,000 + 4,999): the contrast example. Walk every column, pause, and ask the class what is different — the expected answer is 'no carries!' Take a couple of answers; if a pupil says something else, take it, then revoice the correct answer. The point: not every problem needs regrouping. Look at each column first; only carry when the total reaches ten.

The teacher question between examples is the pacing lever — it keeps the watching half of the class active without inventing any per-pupil signal.

This round is for talking it through together — pupils take turns at the board and the class agrees or corrects out loud.

Rotate four pupils through the four columns. Before each new column is added, pause the IWB and ask the class to predict the column total with hands up. Take one pupil's prediction, then check the room with thumbs up (agree) or thumbs sideways (would change it). Revoice the prediction ('so you are saying 4 + 5 + 1 makes 10 — agreed?') before the pupil at the board taps to reveal.

After each carry lands, ask the class to name the destination column the carry just moved into and take a quick answer ('tens!', then later 'hundreds!', then 'thousands!'). That teacher question is the pacing lever — it keeps the watching half of the class active across the cascade without inventing a per-pupil signal.

Watch for the cascade: 4 + 5 makes 9, but the carry from the units pushes it to 10, which then sends another carry into the hundreds. Slow down at that moment — that is the cascade idea from Example 2 turning up live.

This round is the practice bank — pupils take turns at the board, check each answer, and the class confirms before moving on. The same 6-problem bank reruns at home as tonight's homework, so keep the board work brisk rather than over-explaining.

Aim for about 90 seconds on problems 1–4, then slow down to two minutes each on problems 5 and 6 — those are the cascade-with-five-digit-answer cases that catch pupils out. If a problem stalls, take the answer, name the regroup that caught the class out, and move on — depth is what the homework bank is for.

Watch for the two ways the cascade catches pupils: forgetting the carry-1 from the previous column (the answer ends up one too small), and writing the carry-1 in the same column as the answer instead of above the next column. Both surface most clearly on problems 5 and 6.