Take three hands-up answers, not open call-outs. Give five seconds of quiet think-time before any hands go up. Resist explaining yet — the rival strategies are the whole lesson; this is just to make pupils notice that subtraction has more than one route.

Walk the three snapshots in order, one at a time. Pace yourself — pupils need to see each jump arc land before the next one fires, and they need the short 'works best when…' line landing in plain English after each one.

• 73 − 28 counting on: ask 'why did we jump to 30 first?' The friendly stop matters. Revoice the 'close together' line in your own words.
• 73 − 28 take away: same numbers, same answer, different picture. Pause here and make pupils name what changed (the starting number, the direction of the arrow).
• 305 − 178 decomposition: ask the class to call out the chunks (100, 70, 8) before you fire each back-jump. Then point at the 'bigger or messier' line — that is the rule of thumb they will use in the next step.

This round is for talking it through together — pupils take turns at the board and the class agrees or corrects out loud.

Before each board pupil drags, take a quick prediction from the class — which strategy would you choose here, and why? Hear one or two, then let the pupil at the board show their route.

Force the board pupil to name their strategy first before they touch the screen. The naming is the thinking — if they jump straight to drawing, pause them and ask 'which strategy?'

• 65 − 39: most pupils will pick counting-on (39 → 40 → 65). Good — say so out loud.
• 84 − 27: take-away or counting-on both work. Let two pupils show both routes side by side if time allows — explicitly tell the class both routes are correct, you want to compare them.
• 412 − 246: decomposition is the natural fit (back 200, back 40, back 6). If a pupil reaches for take-away here, ask them 'how big would your back-jump need to be?' — that usually moves them.

This round is the practice bank — pupils take turns at the board, check each answer, and the class confirms before moving on. The same 4-round bank reruns at home as tonight's homework, so keep the board work brisk rather than over-explaining.

Run the rounds in order. Between rounds, ask one quick question: 'which strategy fits these best?' — bonds-to-20 lend themselves to counting-on, bonds-to-100 to take-away from a hundred, and mixed two-digit subtractions to whichever feels efficient. Don't let any round drag past sixty seconds.

Strategy talk over score: if a pupil gets a fact wrong, ask the class which strategy might have worked — not just what the answer is. The fluency is downstream of the strategy choice.