Open real scissors slowly at the front, or use the shape-card fan. Take two or three hands-up answers, not open call-outs. Hold out for the word 'corner' — connect the square corner of the copybook to the idea of a right angle without naming acute/obtuse yet.

Use a folded-paper right-angle checker held against each angle in turn: a clearly narrow angle (acute), a clearly wide angle (obtuse), an angle just under a right angle (still acute), and one just over (obtuse). The close-to-square pair is the make-or-break — hold the checker still and ask the class to predict before you reveal. Say smaller than the corner and bigger than the corner as you go; keep degrees out of it.

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

This is explore mode: any drop is accepted so the class can reason aloud. Prompt each pupil to picture holding the square corner against the angle before dropping it. The just-bigger-than-a-right-angle card is the one to slow down on — revoice: it opens a little wider than the corner, so it is obtuse. Rotate four pupils across the rounds.

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.

Challenge mode bounces wrong drops and confirms with Check. On the tilted-angle round, remind the class the turn of the angle does not change how wide it opens — compare the opening, not the direction it points. The exact-right-angle round is where pupils second-guess: an exact square corner is neither acute nor obtuse.