Domino

A standard double-six domino set contains 28 tiles. By cataloging the 27 tiles present in the image: [2,4], [3,5], [0,2], [1,4], [3,6], [1,1], [4,4], [1,6], [0,1], [0,0], [4,4] (Wait, checking for duplicates and counting): The tiles present are: 0-0, 0-1, 0-2, 0-3, 0-4, 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. Upon systematic comparison against a full set, calculations show that the 0-5 (blank-five) tile is missing from the image.

By systematically checking all 28 possible domino combinations in a standard double-six set, I identified that the domino [4, 5] is missing from the image. All other combinations from [0, 0] through [6, 6] are present in the displayed 27 dominoes.

The excluded domino is the double zero tile

By systematically going through all 28 dominoes in a standard double-six set and comparing with the 27 shown in the image, I can identify which one is missing. After cataloging all visible dominoes, the [0,3] domino (blank-three) appears to be absent from the image.

Counting the pips on the 27 shown tiles, the face ’1’ appears only six times and the face ’4’ appears only six times while every other number appears seven times; thus the missing domino is [1,4].

By counting the occurrences of each number across all halves of the 27 dominoes in the image, the number 3 appears 7 times and the number 5 appears 7 times, while all other numbers (0,1,2,4,6) appear 8 times each, indicating that the missing domino is the one pairing 3 and 5.

After identifying all dominoes in the image, I found all dominoes in the standard double-six set except [0,6]. The dominoes with 0 on one side that are present are: [0,0], [0,1], [0,2], [0,3], [0,4], and [0,5]. The domino [0,6] (blank on one side, six dots on the other) is the only one missing from the complete set of 28 dominoes.