This is recall, not a cold open: pupils have already met ×100 in your place-value work, so confident hands should appear. Give 5 seconds of silent thinking first, then take three hands-up answers, not open call-outs. Listen for any pupil who says multiply by one hundred — that is the move we will unpack across the lesson, and naming it now flags the lens to look through.

Walk each example aloud, one at a time. Before tapping each rung, hold the screen and ask the class which rule applies — ×10, ×100, ×1000, or one of the divides? Take a couple of answers, then tap to reveal and revoice whoever had it right. That keeps the class predicting before they see the result.

• 4.7 m → 470 cm: ask 'why ×100?' — because one metre IS one hundred centimetres.
• 0.085 km → 85 m: ×1000 — because one kilometre IS a thousand metres. The leading zero on 0.085 vanishes as the digits step three columns left.
• 250 mm → 25 cm: this one goes the OTHER way (÷10) because we are moving UP to a bigger unit. The 10 mm in one cm rule is at work.
• 1.5 km → 1,500 m: ×1000 again. Same rule, bigger starter number — the digits step three columns left.

Anchor the rule before moving on: a smaller unit needs a bigger count of them; a bigger unit needs a smaller count.

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

For each length, set the starting value and its unit, take a quick prediction of the rule (×10, ×100 or ×1000), then tap the destination rung — the digits walk across the place-value columns one step at a time and the ×10 / ×100 / ×1000 step lights up between the rungs as the answer lands. Three named lengths in this order: 3.2 m → cm, then 0.4 km → m, then 75 cm → mm.

Keep the class predicting the rule before the rung is tapped, not reading the result after — the walk itself is the confirmation, so there is nothing to press.

Watch for two slips: pupils saying 'the decimal point moves' (it does not — the digits move past it), and pupils who lose the rule going from km to mm because that is three jumps, not one. Reanchor on the chain in the next step.

This round is the practice bank — pupils take turns at the board, check each answer, and the class confirms before moving on. Six challenges in total; aim for about 1.5 minutes on each of the one-step and two-step moves, and slow down for the km → mm stretch where pupils need to count the ×10s before solving (about 4 minutes including the unpack).

For the stretch, pause and ask 'how many ×10s do we need?' before letting them solve. The answer is three — that is the whole point of the lesson.

Watch for pupils confusing direction: going from km to mm makes the NUMBER bigger; going from mm to km makes it smaller. Smaller unit, bigger count.

If the class flies through the six and a couple of minutes remain, the activity holds three extension challenges (trickier km↔cm and m↔mm jumps); take one or two as bonus board turns rather than starting a new explanation.