Take three hands-up answers, not open call-outs. Don't confirm or correct yet — let the doubt sit. The 2/7 claim is the misconception this whole lesson dismantles, so resist explaining; just gather a couple of gut reactions and move on.

Walk each example one at a time.

• 1/4 + 1/3 — point straight back at the hook: 'this is why 2/7 was wrong — the slices have to be the same size first.' Twelfths is the smallest size that fits both quarters and thirds.
• 5/6 − 1/2 — only one fraction needs renaming here, because 6 already works for both. Stress the simplify step at the end: 2/6 is correct but 1/3 is tidier.
• 3/4 − 2/3 — both rename to twelfths; the answer 1/12 is already in simplest form, so nothing to tidy.

The common denominator is the make-or-break move — name it aloud every time before any adding or subtracting.

This round is for talking it through together — pupils take turns at the board and the class agrees or corrects out loud. The single set of strips loads on the first problem (2/5 and 3/10, unrenamed); after each problem, clear the shading and re-shade by hand for the next pair so the one widget carries all three in turn.

• 2/5 + 3/10 — the strips start as 2/5 and 3/10. Ask which fraction needs renaming. Only the fifths do: 2/5 becomes 4/10. Then 4/10 + 3/10 = 7/10, already simplest.
• 1/2 + 1/4 — clear the strips, re-shade a half and a quarter, then rename the half to 2/4 and add to get 3/4.
• 7/8 − 3/4 — clear and re-shade, rename 3/4 to 6/8, take it from 7/8 to leave 1/8.

Listen for pupils who try to add the bottom numbers — send them straight back to the strips so the size mismatch is visible.

This round is the practice bank — pupils take turns at the board and the class confirms each answer before moving on. Keep the board work brisk rather than over-explaining.

• The earlier targets land on one renamed denominator; the last two need twelfths.
• The tool checks the final shaded answer only, so the renaming step is confirmed aloud by the class before each Check, not by the widget.
• While one pupil shades, the watching class agrees or corrects the renaming aloud — that confirmation is their job each turn, so let a short gap sit for it rather than rushing the Check.

Tie the day's work back to the opening pizza: Aoife and Conor ate 7/12 of it together, not 2/7. The renaming habit is the bridge into mixed numbers next lesson.