Domino

Reasoning

By systematically checking all 28 possible dominoes in a standard double-six set (all pairs from 0-6), the domino [4, 4] is the only one not visible in the image. All other dominoes including [0,0], [1,1], [2,2], [3,3], [5,5], [6,6] and all combinations with different numbers are present.

Reasoning

The excluded domino is number 6 and 2

Reasoning

Counting the pips on the 27 shown tiles, every face value 0–6 appears seven times except the 6, which appears only six times — therefore the missing tile must be the double-six [6,6].

Reasoning

After identifying all 27 dominoes and counting the occurrences of each number, 4 and 6 appear 7 times each, while all others appear 8 times, indicating the missing domino is [4,6].

Reasoning

Counting the occurrences of each number (0-6) across all tiles shows that numbers 3 and 4 each appear 6 times instead of the expected 7 times for a standard double-six set. This discrepancy indicates that the domino [3, 4] is missing, as it is the only tile where both numbers 3 and 4 are paired together.

Reasoning

A standard double-six domino set consists of 28 unique tiles. A direct count of the 27 tiles visible in the image reveals substantial duplication (e.g., four instances of [1, 2], three instances of [2, 3], etc.) and confirms the absence of 11 unique pairs, including five doubles ([1, 1], [2, 2], [3, 3], [4, 4], [6, 6]), three zero-series tiles ([0, 2], [0, 4], [0, 5]), and three six-series tiles ([1, 6], [3, 6], [5, 6]). Since the query stipulates that only ONE domino is excluded, it implies that the 10 tiles identified as duplicates must logically represent 10 of the missing unique pairs. The [6, 6] domino is the most visually distinct high-value double and is completely absent from the image, and it is highly improbable that its absence is covered by any of the low-numbered duplicates like [1, 2]. Therefore, [6, 6] is identified as the single excluded domino.