Domino

The excluded domino is number 0 and 0

After categorizing all 27 tiles in the image by their number pairs, the following standard double-six set tiles were found: [0,0], [0,1], [0,2], [0,3], [0,4], [0,5], [0,6], [1,1], [1,2], [1,3], [1,4], [1,5], [1,6], [2,2], [2,3], [2,4], [2,5], [2,6], [3,3], [3,4], [3,5], [3,6], [4,4], [4,5], [4,6], [5,6], [6,6]. The only tile missing from the complete 28-tile set is the double-five [5,5].

A standard double-six domino set contains 28 tiles representing all unique pairs of numbers from 0-6. By systematically checking each possible combination in the image, I identified that the domino [2, 4] is missing from this set of 27 dominoes.

Going through all 28 dominoes in a standard set (0-0, 0-1, 0-2, 0-3, 0-4, 0-5, 0-6, 1-1, 1-2, 1-3, 1-4, 1-5, 1-6, 2-2, 2-3, 2-4, 2-5, 2-6, 3-3, 3-4, 3-5, 3-6, 4-4, 4-5, 4-6, 5-5, 5-6, 6-6), I identified each domino visible in the image. After careful analysis, the domino [0,3] (blank/three) appears to be missing from the set of 27 shown.

I identified all 27 tiles in the picture and compared them to the full double-six set. Every unordered pair from 0–6 appears except the 4–5 tile; counts of pips for 4 and 5 are each one short of the expected total, so the missing domino is [4,5].

A standard double-six domino set contains 28 dominoes. By systematically examining the image, all dominoes involving 0 can be identified except one: [0,0] is present (horizontal in row 4), [0,1] is present (vertical), [0,2] is present (horizontal in top row and row 4), [0,3] is present (vertical), [0,4] is present (vertical in row 2), and [0,6] is present (vertical in bottom row). The only missing domino in the 0-series is [0,5], which would be a domino with a blank half and a half with 5 dots (center plus four corners). Additionally, the number 5 appears in other dominoes like [1,5], [4,5], and [5,6], confirming that only the [0,5] combination is absent from the set.