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.

Real ruler at the front, not on screen. Four objects, each one: estimate aloud first, then measure live.

Key move: line the 0 mark exactly with one end, then read the far end. Head off the common slip of starting from the metal end or the 1.

Parallax: keep your eye square over the far end, not off to the side.

Crayon about 6 cm. Pencil 8 cm 5 mm. Copybook edge about 12 cm. Rubber 4 cm 5 mm.

For pencil and rubber the end falls between marks, so count on: eight... one, two, three, four, five millimetres.

Awkward shapes they will meet later: flat hand, 0 at the thumb tip, read to little finger. Scissors, close them, 0 at the tip of the closed blade, read to end of handle.

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'.

These are the practice questions — 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.