Take three hands-up estimates, not open call-outs. Don't confirm or correct any yet — hold the guesses for the class to test against once they know the method.

Resist the urge to name the answer here — the whole lesson is about how we can work it out instead of counting one cube at a time. If you happen to have a real box and a tub of cubes to hand, holding them up makes a good extra prompt, but the picture on the board is all you need.

• 5 × 3 × 2 — point to one layer of 15 cubes, then the second layer on top; that is area-of-base times height (15 × 2 = 30).
• 6 × 4 × 3 — ask for the base layer first (24), then how many layers (3), before revealing 72.
• 4 cm cube — 'all three sides the same — so it's 4 × 4 × 4'; hold out for pupils to say 64 rather than reading it off.

Keep saying the unit aloud: cubic centimetres, cm³. This is where pupils drop the cubed unit later.

Talk this one through together — pupils take turns at the board and the class agrees or corrects out loud.

Set the three sliders in the 3D mode. For each box, ask for the base-layer count, then the number of layers — so what's the volume? — then check against the live readout. Three boxes, a turn at the board each, and a full predict-check cycle on every one fills the time. Watch for pupils who add the three dimensions instead of multiplying; catch it on the first box.

This is the practice round — pupils take turns at the board, check each answer, and the class confirms before moving on. Keep the board work brisk rather than over-explaining.

The last task reverses the rule: volume ÷ (base area) gives the missing height. Hold out for the class to spot that 48 ÷ 12 = 4 before anyone guesses. Every pupil can enter on the cube; the reverse problem is the stretch.