Splitting a number up like that has a maths name — we call it partitioning.
Roughly how much is 23 × 3? Guess in your head first, then a few of you will share your guess. Now here is the clever bit: what if we broke twenty-three into twenty and three to make it easier?
Ask pupils to guess quietly, then take two or three estimates from raised hands — not open call-outs. Draw out the idea of splitting 23 into 20 + 3 and name it as partitioning. Don't work the answer yet — the split is the hook.
Each rectangle splits the two-digit number into a tens part and a units part. Watch how each part gets its own area, and how the two areas add up to the whole answer.
14 × 2: establish the two parts; name area and part-product in plain words. Tens 10 × 2 = 20, units 4 × 2 = 8, add 20 + 8 = 28.
23 × 3: pause before revealing, ask which part will be bigger, take two answers. Tens 20 × 3 = 60, units 3 × 3 = 9, add to 69.
Before the next one, ask who thinks the units part will jump past ten; take an answer or two, then reveal.
16 × 4: the trap. Units 6 × 4 = 24 is bigger than ten, but we still just add it on. Tens 10 × 4 = 40, add 40 + 24 = 64. Say it slowly.
32 × 3: clean split to consolidate. Tens 30 × 3 = 90, units 2 × 3 = 6, add to 96.
Now let's build one together. One pupil comes to the board and sets 15 × 2 on the area model, and the rest of us watch and agree the two part-areas out loud before anyone adds. We split fifteen into its tens part and its units part, find the area of each part, and add the two areas to reach the total. After this one we build 22 × 3 and 24 × 4 the same way, one at a time on the same model.
This round is for talking it through together — pupils take turns at the board and the class agrees or corrects out loud.
For each fact, set the two factors so the rectangle fills, then have a pupil read the tens part-area and the units part-area before anyone adds. Revoice, using this round's own numbers: so for 22 × 3 the tens part is worth sixty, the units part is worth six, and together that is sixty-six. Watch for pupils who multiply only the tens and forget the units part. After 15 × 2, reset the model to build 22 × 3, then 24 × 4, one at a time.
In your maths copy, work 24 × 3 and 15 × 3 by partitioning. For each one, write the tens product on one line and the units product on the next line, then add them to find the total.
Walk the room glancing for a tens line and a units line under each fact — this is whole-class copybook practice, not marking. Watch for pupils who write only one product, and remind them both parts must be multiplied.
Today we build and read the area for these, in order: 13 × 2, then 21 × 4, then 17 × 3, then 26 × 3. Each one splits into a tens part and a units part, and for 17 × 3 and 26 × 3 the units part is bigger than ten — so say each part-area aloud before we add.
These are the practice questions — 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.
13 × 2 and 21 × 4 have tidy units parts. 17 × 3 (units 7 × 3 = 21) and 26 × 3 (units 6 × 3 = 18) are the ones where the units part is bigger than ten — that is the wrinkle these two add. Callout: is the units part bigger than a ten? We still just add it on to the tens part.
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