Take three hands-up answers on the stadium crowd, not open call-outs. Then jot two or three real four-digit numbers pupils name (a crowd, the year, a price) on the board and read each one aloud slowly. Keep it to a minute or two of talk.

First snapshot, 1,000: ten hundreds trade for one thousand-cube. Stress the trade, and point to the brand-new thousands column opening on the left. Link back: ten tens once made one hundred.

Second, 1,300: one in the thousands, three in the hundreds, zero tens, zero units. Read slowly; point at the empty tens and units, the zeros hold the places open.

Third, 2,400: before revealing, ask how many thousand-cubes they expect. Two thousands, four hundreds. Read aloud together to confirm two thousand, four hundred.

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

Call a friendly number, send one pupil up to build it, and have the class read it back as so many thousands and so many hundreds. Listen for pupils reading 1,500 as "fifteen hundred" — accept it, then revoice as one thousand five hundred and point at the single thousand-cube. Rotate four pupils.

Pupils take turns at the board, check each answer, and the class confirms before moving on. Keep the board work brisk rather than over-explaining.

For each target, add a 'how is this just our place-value rule with one more column?' callout. Pause on 3,000 — three thousand-cubes and nothing else — and ask the class what holds all those empty places open.