How many dominoes are there in a domino set?

The number of dominoes in a set can vary, but the most common set is a double-six domino set, which contains 28 dominoes.

Here's why:

* Each domino has two sides.

* Each side can show a number from 0 to 6.

* Therefore, there are 7 possible numbers for each side.

* To calculate the total number of dominoes, we use the formula: (n+1)(n+2)/2, where 'n' is the highest number on a domino (in this case, 6).

* Applying the formula: (6+1)(6+2)/2 = 7*8/2 = 28

So, a standard double-six domino set has 28 dominoes.