Take two or three hands-up ideas, not open call-outs. Someone will usually say count the squares — that is exactly where we are heading.

Do not resolve it yet; the counting method is built in the next step.

Point to the fully-covered squares first, count them aloud, hold out so pupils catch any you skip.

The edge rule: count a part-square only if the leaf covers more than half of it, ignore less than half.

Point to one barely clipped — ask, does it count? Then one clearly more than half — that one counts.

Make the balance explicit: a big-part square counted whole takes a bit too much, a small-part square dropped leaves a bit out, they roughly cancel.

Alternative for the edge: trace two roughly-half squares and pair them — this one and that one make one whole together.

Ask pupils to predict a rough total before you announce it.

Note: the on-screen shape tool draws straight edges only, so this runs on the annotated leaf diagram, not the shape tool.

This is the practice round — talk it through together, with pupils taking turns to point at squares on the board while the class agrees or corrects out loud.

Split the job into two tallies: whole squares first (write the running count on the board), then part-squares. Insist the class calls out for each edge square: more than half — does it count? Then pair the halves aloud.

The estimate lands close to, not exactly on, whatever an individual pupil expected — say so: two people who count carefully can still land a square or two apart, and both are fair estimates.

Pupils work each shape on their own squared paper at their desks while you circulate. Keep it brisk; the class confirms each shape's estimate aloud at the end.

The printed stone and leaf templates are the canonical kit here — they print onto squared paper so every pupil has the same outline. A real stone or a real leaf is a nice optional upgrade if you happen to have them, but nothing needs to be brought in; the pupil's own hand is always to hand.

Watch for two slips: counting a barely-clipped square as whole, and forgetting to pair the halves. The stretch is the key beat — when a pupil re-counts and gets a slightly different total, that is the evidence that this is an estimate. Bring one such case to the whole class.