Hold a pencil beside a demonstration ruler. Take three hands-up estimates for the pencil, not open call-outs. Don't reveal the real length yet — the point is the estimate.

Steer the second question toward the idea that very small things need smaller units. Don't name millimetres yet; let it surface in Watch and Notice.

This is a real demonstration at the front with a ruler, not an on-screen widget. Measure each object live so pupils see the zero-alignment.

• Each time say the estimate aloud first, then slide the object so its end sits exactly on 0.
• Make the parallax point: keep your eye square over the far end, not off to the side.
• For the pencil and rubber, count the little marks past the whole centimetre: 'eight... and one, two, three, four, five millimetres'.
• Model the awkward shapes the class will meet later: for a flat hand, zero at the thumb tip; for scissors, close them and put zero at the tip of the blade.

Common slip to head off: starting the measure from the metal end or the 1, not the 0.

This round is for pupils to measure at their desks with their own rulers — circulate and catch alignment slips on the spot. The class reads aloud and you reconcile any disagreement as you circulate.

Have pupils write the estimate down before measuring (a quick number in the copy or on the record sheet), so the within-1 cm star-check in the next step has something to compare against. Name one object at a time (pencil, rubber, ruler edge, copybook edge). Pause after each so everyone reads before you call the agreed answer.

• Watch for pupils starting at the 1 or the ruler's edge instead of 0.
• Watch for an eye angled off to the side — remind them to look straight down.
• Revoice a good answer in cm and mm: 'so that's eight centimetres and five millimetres'.

This round is the practice bank — pupils measure real objects at their desks with their own rulers, recording estimate and measurement on the record sheet or in the copy. Keep the pass-on rhythm brisk; the class confirms each reading aloud at the end.

Run the five items in order, easiest first (pencil) building to the trickier handspan, which was modelled in Watch and Notice. The five core measurements are the work for this slot; the 'find something exactly 7 cm' is a clear stretch-only beat for pupils who finish the five early.

• Handspan is awkward: remind them to keep the hand flat and the zero at the thumb tip, just as in the demo.
• For the 7 cm hunt, the value they place is what they measure and check — accept anything that genuinely reads 7 cm.
• Confirm each agreed answer aloud before moving on.

For the next lesson, having a metre stick and a few longer objects (door, shelf, corridor stretch) ready helps pupils feel the jump from cm to m.