Take three hands-up guesses, not open call-outs. Don't confirm the answer yet — the point is to make pupils curious about how many centimetres hide inside one metre. If someone answers 'three' they are counting the rulers; steer them back to counting the little centimetre marks.

Point at the jump chip between the two rungs and say the word hundred as each digit lands.

• 1 m → 100 cm — the anchor fact; ask the class to say it back.
• 3 m → 300 cm — pause before the reveal; ask how many hundreds?
• 1 m 50 cm → 150 cm — the hundred from the metre joins the loose fifty.
• 2 m 50 cm → 250 cm — two whole hundreds plus a leftover fifty. Then run it aloud the other way: ask how many whole hundreds are inside 250, and what is left over? so the class hears the reverse split before they meet it in the challenge.

Talk this one through together — pupils take turns at the board and the class agrees or corrects out loud.

Set the clean metre-to-centimetre jumps on the ladder so everyone hears the hundred pattern. The last item goes the other way, so work it on the board rather than the ladder: ask how many whole hundreds are inside 250? before anyone writes, and hold out for a pupil to answer.

This is the practice round — 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.

The last item goes the other way, from centimetres back to metres. On 250 cm ask how many hundreds, and what is left over? before the pupil types. The mixed answer is 2 m 50 cm.