Trace a finger right around a rectangular page on the IWB, ending back at the starting corner. Take two or three hands-up answers, not open call-outs. Listen for add up the sides or measure all the way round — that is exactly where the lesson is going.

Touch every side once as you add, saying the running total aloud.

Triangle: 3, then 4, then 5, landing on 12 cm.

Square: four equal sides of 4 cm, total 16 cm. A first gentle link to multiplication, but keep it addition here.

Rectangle: name the long pair and short pair, add all four to reach 16 cm.

Make-or-break: every side added exactly once, none missed or double-counted.

This round is for talking it through together — one pupil works at the board while the rest of the class reads and totals aloud, agreeing or correcting.

Call a pupil to the board to touch along each side of the shape in turn while the class reads each length aloud and keeps a running total. Watch for anyone who skips a side or counts a side twice — revoice with did we touch every side exactly once?. Rotate three or four pupils across the rectangle and then redraw it as a square so the class sees the same rule on a different shape.

These are the practice questions — real objects circulate around the room (or sit at stations) and pupils measure each one with their own string and ruler. Keep the pass-on rhythm brisk; the class confirms each reading aloud at the end.

Hand out cards (about 4 cm by 6 cm), string, rulers and the Perimeter Measuring Record sheet. Sub-prompts of rising difficulty: find the perimeter of the card; find the perimeter of your own copybook to the nearest centimetre; find the perimeter of a triangle card; then compare two cards by holding the first card's string around the second card's edge to predict which is longer, then check by measuring. Watch for pupils pulling the string tight enough to follow the corners but not stretching it. The class confirms each reading aloud.

Brisk recap of the first three bullets, then teach equal sides with one full worked example (do not defer this skill).

Draw a rectangle. Label only one long side 5 cm and one short side 3 cm. Leave the other two sides blank.

Worked steps: (1) Point to the long pair, opposite sides are equal, so write 5 cm on the missing long side. (2) Point to the short pair, write 3 cm on the missing short side. (3) Add every side once: 5 + 3 + 5 + 3 = 16 cm.

Slip to watch: pupils who add only the two given numbers (5 + 3) and stop. Prompt: have we gone all the way around, each side exactly once?

Close by linking back: equal sides do not change the rule, they just tell you the lengths you still need to add.