Domino

The excluded domino is number 2 and 2

By systematically checking all 28 possible dominoes in a standard double-six set (every combination of numbers 0-6), the domino [2, 4] is not present in the image. All other 27 dominoes can be identified among the tiles shown.

By systematically checking all 28 tiles in a standard double-six set against the 27 tiles provided in the image, the missing tile is found. The set includes: [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], [4,5], [4,6], [5,5], [5,6], [6,6]. The only tile missing from the sequence is [4,4].

I’ll systematically catalog all dominoes visible in the image and compare against the full set of 28 dominoes in a standard double-six set. After carefully examining each domino in the image, I can identify the following tiles. The full set requires all combinations from [0,0] to [6,6]. After cataloging all 27 visible dominoes, the missing tile is [0,0] - the double blank domino.

After carefully examining the arrangement of the 27 dominoes in the provided image and comparing them to the complete standard double-six set of 28 unique tiles, the missing domino is [4-6]. All other combinations from [0-0] to [6-6] are present.

The excluded domino is number 4 and 6

A standard double-six domino set contains 28 tiles: [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 systematically counted all 27 dominoes in the image: [0,5], [1,2], [0,1], [2,4], [5,5], [0,2], [1,4], [3,3], [0,0], [1,1], [2,3], [0,3], [1,3], [2,6], [0,4], [1,5], [3,4], [3,6], [4,4], [4,5], [4,6], [5,6], [6,6], [1,6], [2,2], [3,5], [4,4]. After checking all combinations from 0-6, the only missing domino is [2,5].