Take three hands-up answers, not open call-outs. Some pupils will guess-and-check; that is fine as an entry point. Do not reveal the letter-symbol method yet — the point of the hook is to leave them curious about a tidier way than trial and error. Give five seconds of quiet think-time before any hands go up.

Work each story live on the board. Do not read solutions off the screen. For Story 1, hold out until a pupil names the hook number, then show that 2n + 5 = 17 is that story in symbols.

• Story 1, number trick (two undos)
  Equation: 2n + 5 = 17
  Undo add 5 first: 2n = 12
  Undo double: n = 6
  Label each undo aloud. Check: 2 × 6 + 5 = 17.
• Story 2, pencils (one undo)
  Trap: mixing euro and cent. Say work in cent so the numbers stay whole (€3 = 300c).
  Equation: 50p = 300
  Undo: p = 6
  Meaning: 6 pencils. Check: 6 × 50c = 300c.
• Story 3, three undos
  Equation: 3n + 2 − 4 = 10 (done in order: ×3, then +2, then −4).
  Undo take-away 4 first: 3n + 2 = 14
  Undo add 2: 3n = 12
  Undo ×3: n = 4
  Check: 3 × 4 = 12, + 2 = 14, − 4 = 10.

Before Story 3, pause and pick a pupil to name what got undone first in the pencils problem, so the three-undo story lands on a fresh class. Slip to watch: undoing in story order instead of reverse, or dividing first when something was added last. Keep asking which operation happened last? before anyone touches the equation.

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

Do the treble-and-take-away one on the interactive first. Then work the apples problem (6b = 30, one undo) and the chairs problem (4r + 3 = 27, two undos) by hand on the board, with pupils calling each step. The apples one is a deliberate breather after the two-step trick; the chairs one adds the second undo back in. Keep the three brisk — one interactive problem and two quick board problems is an eight-minute beat, not longer. Keep asking which operation do we undo first, and why? before anyone moves.

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 taxi problem is the one that catches people: pupils want to write 2k + 4 but then divide by 2 first. Ask what was added last? so the €4 start comes off before the €2-per-km is undone. On the fundraising problem there is no fee to remove, so it is a single undo — a deliberate easier rung. Fast finishers write their own puzzle quietly while you circulate; do not send them to a device. The same four puzzles are on the printable worksheet for pupils to redo at their own pace.