Split #21 — the solution

The three rounds from October 20, 2026: twelve numbers each, split into four groups of three that add to the target — the one way each round allows, with its decoys and where the reasoning starts.

Round 1 — target 29

The numbers: 5, 14, 20, 9, 13, 11, 12, 2, 3, 1, 18, 8. 3 decoys.

The groups: 5 + 13 + 11, 14 + 12 + 3, 20 + 1 + 8, 9 + 2 + 18.

The decoys — triples that add to 29 but are not in the answer: 14 + 13 + 2; 9 + 12 + 8; 3 + 18 + 8.

Where to start: 5, 20, 11 and 1 sit in only one on-target triple, so their groups are certain — start there.

Round 2 — target 30

The numbers: 11, 7, 20, 4, 16, 8, 5, 1, 17, 12, 13, 6. 5 decoys.

The groups: 11 + 7 + 12, 20 + 4 + 6, 16 + 1 + 13, 8 + 5 + 17.

The decoys — triples that add to 30 but are not in the answer: 11 + 13 + 6; 7 + 17 + 6; 16 + 8 + 6; 5 + 12 + 13; 1 + 17 + 12.

Where to start: 20 and 4 sit in only one on-target triple, so their groups are certain — start there.

Round 3 — target 33

The numbers: 3, 11, 15, 13, 14, 5, 12, 20, 8, 6, 16, 9. 7 decoys.

The groups: 3 + 14 + 16, 11 + 13 + 9, 15 + 12 + 6, 5 + 20 + 8.

The decoys — triples that add to 33 but are not in the answer: 11 + 14 + 8; 11 + 6 + 16; 15 + 13 + 5; 13 + 14 + 6; 13 + 12 + 8; 5 + 12 + 16; 8 + 16 + 9.

Where to start: 3 and 20 sit in only one on-target triple, so their groups are certain — start there.

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About Split

Split is Noggin’s number puzzle, on the second shelf: twelve numbers into four groups of three, three rounds a day, outside the daily line-up. How to play Split, or play today’s.