Bring the finished symmetric design up on the IWB grid and take three hands-up answers. Don't confirm anything yet, just gather the vocabulary the class already has (flip, slide, mirror line, across, up).

Listen for whether pupils reach for grid-reference language on their own; you will build on it in the next step.

On the symmetry snapshot, run a finger from a left square across to its mirror partner and say same distance, opposite side. Read the grid reference of two shaded squares out loud as across first, then up so the class hears the order even though the tool stores squares as row and column.

Pause between the two snapshots: ask who can tell me a square on the left and its mirror partner on the right? before moving on, so the class settles the symmetry idea before the points appear.

On the co-ordinate snapshot, pose a quick question before you read each dot: who can tell me its reference, across first? Take one answer, then read it back three across, two up. Hold out for the across-first habit — this is the slip that ends the year's location work in the wrong square.

This round is for talking it through together — no marking yet. Take hands-up answers and revoice.

On the co-ordinate grid, point A is already plotted. Ask pupils to suggest where a vertical mirror line could sit so the point would flip onto a match, then agree the reference of point A across first, then up.

Then take two predictions for how far the point lands after a flip, and check by reflecting it on the grid. Revoice: the point has to be the same number of squares from the line on each side.

This round is for talking it through together — no marking yet. Pupils take turns at the board and the class agrees or corrects out loud.

Say the mirror line is at 5 across and trace the vertical line each time so pupils count squares from a line they can picture, even though it is not a plotted point.

Individual pupils come up to plot each point; the rest of the class calls the new grid reference before the pupil taps. Reconcile any disagreement about across-versus-up on the spot.

Watch for the reflection slip where pupils count from the shape rather than from the mirror line. Revoice a good answer: so the corner has to be the same number of squares from the line on each side.