Take three hands-up estimates, not open call-outs. Don't confirm or correct yet — the answer (eight glasses) lands later in the lesson. Hold on to your guess, we'll check it near the end.

Point at the flat middle of each surface as the class reads it aloud.

Meniscus: water climbs where it touches the sides, so read the middle, eye level.

Glass 250 ml — scale to 1 l, minor marks every 50 ml. Say a quarter of a litre so the fraction link resurfaces.

Bottle 500 ml — halfway to one litre, half a litre.

Carton 1,000 ml, filled to the top litre mark. Ask: what is 1,000 ml in litres? Take two hands-up answers before the fourth jug.

Big bottle uses a bigger scale — marks every 100 ml, up to 2 l. Confirm pupils have noticed the change before they read. Level sits a quarter past 1 l: 1.25 l, the same as 1,250 ml.

Try Together: work through this on the board with the class, one pupil driving while the others predict and check.

Individual pupils drag the level to each target while the class calls out where it should stop. Watch for pupils who read the scale by the top of the curve rather than the flat middle. Revoice a good reading: eye level with the mark, read the dip. Notice with the class that 500 ml is exactly halfway and 750 ml is three of the four quarter-marks.

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 450 ml target lands exactly on a minor mark between the 400 and 500 marks. The 1.25 l target switches to the 2 l jug (marks every 100 ml), which the board now states — confirm the class has noticed the change before that one. Have the class predict where each level will stop before the pupil at the board drags it.