Give five seconds of quiet think-time, then take three hands-up guesses, not open call-outs. Do not confirm or correct yet — the guessing is the hook, the levelling comes next. Listen for anyone who already lands near the middle height; you can revoice their reasoning in Watch and Notice.

Set one 4, 6, 8: level them live so all three sit at 6, point to the mean on the overlay. Then show the two routes meet — total 4 + 6 + 8 = 18, shared into 3 gives 18 ÷ 3 = 6. Call the mean the fair-share height.

Set two 12, 9, 15, 4: take two predictions first, then reveal total 40, four values, 40 ÷ 4 = 10 — mean sits between the values, equal to none of them.

Set three 0, 3, 6: turn-and-name the equal height. Hold out for the empty tower still counting — divide by 3, not 2, giving 3. Common slip is ignoring the zero tower; revoice an empty tower is still a tower.

Pupils measure and level at their desks with their own cubes — circulate and catch alignment slips on the spot. The class reads aloud and you reconcile any disagreement as you circulate.

The total is 24 and there are 4 towers, so 24 ÷ 4 = 6 — every tower should end at 6 cubes. Watch for groups who stop levelling too early or who forget to count all four towers when dividing. Ask one group to show their levelled towers to the class and another to show the add-and-divide line, then confirm the two match.

This is the practice round — pupils take turns at the board, check each answer, and the class confirms before moving on. Keep the first three problems brisk to protect two or three minutes for the missing-value problem, which is the hardest.

Answers: rainfall (4 + 6 + 8) ÷ 3 = 6 mm; hurler (3 + 5 + 5 + 7) ÷ 4 = 5 points; savings (2 + 3 + 0 + 4 + 6) ÷ 5 = 3 (the €0 still counts as a value, so divide by 5); missing sweets: mean 8 × 3 = 24 total, minus 6 and 11 leaves 7. The missing-value one reverses the rule — multiply the mean by how many to get the total back, then subtract the known values, exactly like the worked example at the top. Ask the class to predict whether the third friend has more or fewer than 8 before revealing.