Take three hands-up answers, not open call-outs. Write each suggested rule on the board exactly as the pupil says it ('plus three', 'goes up by three', 'add three each time') so the class can compare the wording later.

Walk each example aloud, one at a time. Do not jump ahead. With four machines to cover, keep the first three brisk and save the most time for the last one.

• Add 3 — settle the class on one agreed wording. Steer them to 'start at 4, then add 3 each time': a rule needs both the starting number and what to do.
• Take 5 — the only word that changed is the verb (add becomes take or subtract). Name that out loud.
• Double — this machine shows separate inputs, each doubling on its own, not a self-feeding chain. Head off 'add 1, then 2, then 4'; revoice as 'each one doubles' so the rule is one move, not a growing list.
• Double, then add 1 — this is the make-or-break example, so give it the most time. On the board, feed the output of one step back in as the next input: 1 doubles to 2, add 1 makes 3; send 3 back in, it doubles to 6, add 1 makes 7. Then show on the board that doing it in the wrong order (add 1 first, then double) gives a different number, so pupils see why the order is part of the rule, not just the teacher saying so.

This round is for talking it through together — pupils take turns at the board and the class agrees or corrects out loud. This machine shows one rule (add 3), so the work is in the wording, not in swapping rules.

Send a number through, then ask the class for the rule in words before sending the next. Hold them to a wording another person could actually use: 'add 3' is fine, 'it gets bigger' is not (bigger by how much?). Keep the watching class with it by turning to a different pupil each time — turn-and-name rather than always the same hands — and revoice the strongest answer back word for word.

This round is the practice bank — 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.

For each machine, get the rule in words first, then predict, then Check. When a wrong wording survives a single pair, ask for an input it would get wrong — that is the test that catches a poor rule. The last two are two-step rules: hold the class to naming both jobs and the order (multiply first, then add), not just one verb. Frame the final machine openly as a stretch, so a pupil who needs two or three tries feels they are doing the task right, not falling behind. Use the six-word line only as an optional extra for those who crack it.

Close by reading back two or three of the class's best-worded rules from today as the standard to aim for.